Index: modules/field/field.form.inc
===================================================================
RCS file: /cvs/drupal/drupal/modules/field/field.form.inc,v
retrieving revision 1.8
diff -u -r1.8 field.form.inc
--- modules/field/field.form.inc	3 May 2009 09:49:32 -0000	1.8
+++ modules/field/field.form.inc	10 May 2009 22:58:47 -0000
@@ -11,7 +11,7 @@
 /**
  * Create a separate form element for each field.
  */
-function field_default_form($obj_type, $object, $field, $instance, $items, &$form, &$form_state, $get_delta = NULL) {
+function field_default_form($obj_type, $object, $field, $instance, $language, $items, &$form, &$form_state, $get_delta = NULL) {
   // This could be called with no object, as when a UI module creates a
   // dummy form to set default values.
   if ($object) {
@@ -287,7 +287,7 @@
 /**
  * Transfer field-level validation errors to widgets.
  */
-function field_default_form_errors($obj_type, $object, $field, $instance, $items, $form, $errors) {
+function field_default_form_errors($obj_type, $object, $field, $instance, $language, $items, $form, $errors) {
   $field_name = $field['field_name'];
   if (!empty($errors[$field_name])) {
     $function = $instance['widget']['module'] . '_field_widget_error';
Index: modules/field/field.attach.inc
===================================================================
RCS file: /cvs/drupal/drupal/modules/field/field.attach.inc,v
retrieving revision 1.15
diff -u -r1.15 field.attach.inc
--- modules/field/field.attach.inc	9 May 2009 19:02:11 -0000	1.15
+++ modules/field/field.attach.inc	10 May 2009 22:58:47 -0000
@@ -171,23 +171,32 @@
   foreach ($instances as $instance) {
     $field_name = $instance['field_name'];
     $field = field_info_field($field_name);
-    $items = isset($object->$field_name) ? $object->$field_name : array();
+    $field_translations = array();
+
+    // Initialize field translations according to the available languages.
+    foreach (_field_available_languages($field, $instance) as $language) {
+      $field_translations[$language] = isset($object->{$field_name}[$language]) ? $object->{$field_name}[$language] : array();
+    }
 
     $function = $default ? 'field_default_' . $op : $field['module'] . '_field_' . $op;
     if (drupal_function_exists($function)) {
-      $result = $function($obj_type, $object, $field, $instance, $items, $a, $b);
-      if (is_array($result)) {
-        $return = array_merge($return, $result);
-      }
-      else if (isset($result)) {
-        $return[] = $result;
+      // Iterate over all the field translations.
+      foreach ($field_translations as $language => $items) {
+        $result = $function($obj_type, $object, $field, $instance, $language, $items, $a, $b);
+        // Store the result into per-language separate fields.
+        if (is_array($result)) {
+          $return[$language] = isset($return[$language]) ? array_merge($return[$language], $result) : $result;
+        }
+        else if (isset($result)) {
+          $return[$language][] = $result;
+        }
+        // Populate $items back in the field values, but avoid replacing missing
+        // fields with an empty array (those are not equivalent on update).
+        if ($items !== array() || isset($object->{$field_name}[$language])) {
+          $object->{$field_name}[$language] = $items;
+        }
       }
     }
-    // Populate $items back in the field values, but avoid replacing missing
-    // fields with an empty array (those are not equivalent on update).
-    if ($items !== array() || property_exists($object, $field_name)) {
-      $object->$field_name = $items;
-    }
   }
 
   return $return;
@@ -201,6 +210,40 @@
 }
 
 /**
+ * TODO
+ */
+function _field_available_languages($field, $instance) {
+  static $field_languages;
+
+  $field_name = $field['field_name'];
+  if (!isset($field_languages[$field_name])) {
+    if ($field['translatable']) {
+      $languages = $available_languages = array_keys(language_list());
+      // TODO: $instance['languages'] might be populated somehow to let users/modules
+      // decide which languages are available for the current instance.
+      // - Should this exist or the following hook invocation should be enough?
+      // - Should this be an instance or a field setting?
+      // $languages = isset($instance['languages']) ? $instance['languages'] : $available_languages;
+      // TODO: Do we need this hook invocation?
+      foreach (module_implements('field_languages') as $module) {
+        $function = $module . '_field_languages';
+        $function($field, $instance, $languages);
+      }
+
+      // TODO: Consider distinguishing between content language and UI language:
+      // probably they should not be tied in any way.
+      // Accept only available languages.
+      $field_languages[$field_name] = array_intersect($available_languages, $languages);
+    }
+    else {
+      $field_languages[$field_name] = array(FIELD_LANGUAGE_NEUTRAL);
+    }
+  }
+
+  return $field_languages[$field_name];
+}
+
+/**
  * @} End of "defgroup field_attach"
  *
  * The rest of the functions in this file are not in a group, but
@@ -225,7 +268,23 @@
  */
 function _field_attach_form($obj_type, $object, &$form, $form_state) {
   // TODO : something's not right here : do we alter the form or return a value ?
-  $form += (array) _field_invoke_default('form', $obj_type, $object, $form, $form_state);
+  $result = _field_invoke_default('form', $obj_type, $object, $form, $form_state);
+
+  // TODO: is this the right way?
+  $languages = language_list();
+  $form['field_translations'] = array(
+    '#type' => 'fieldset',
+    '#title' => t('Field translations'),
+    '#tree' => TRUE
+  );
+  foreach ($result as $language => $field_form) {
+    $form['field_translations'][$language] = array(
+      '#type' => 'fieldset',
+      '#title' => $language === FIELD_LANGUAGE_NEUTRAL ? t('Language neutral') : $languages[$language]->native,
+      '#tree' => TRUE,
+    );
+    $form['field_translations'][$language] += (array) $field_form;
+  }
 
   // Let other modules make changes to the form.
   foreach (module_implements('field_attach_form') as $module) {
@@ -633,13 +692,12 @@
   // Let field modules sanitize their data for output.
   _field_invoke('sanitize', $obj_type, $object);
 
-  $output = _field_invoke_default('view', $obj_type, $object, $teaser);
+  $output = array('field_translations' => _field_invoke_default('view', $obj_type, $object, $teaser));
 
   // Let other modules make changes after rendering the view.
   drupal_alter('field_attach_view', $output, $obj_type, $object, $teaser);
 
   return $output;
-
 }
 
 /**
Index: modules/field/field.install
===================================================================
RCS file: /cvs/drupal/drupal/modules/field/field.install,v
retrieving revision 1.4
diff -u -r1.4 field.install
--- modules/field/field.install	10 Mar 2009 09:45:31 -0000	1.4
+++ modules/field/field.install	10 May 2009 22:58:48 -0000
@@ -58,6 +58,12 @@
         'not null' => TRUE,
           'default' => 0,
       ),
+      'translatable' => array(
+        'type' => 'int',
+        'size' => 'tiny',
+        'not null' => TRUE,
+        'default' => 0,
+      ),
       'active' => array(
         'type' => 'int',
         'size' => 'tiny',
Index: modules/field/field.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/field/field.module,v
retrieving revision 1.7
diff -u -r1.7 field.module
--- modules/field/field.module	26 Mar 2009 13:31:24 -0000	1.7
+++ modules/field/field.module	10 May 2009 22:58:48 -0000
@@ -57,6 +57,11 @@
 /**
  * TODO
  */
+define('FIELD_LANGUAGE_NEUTRAL', '_0');
+
+/**
+ * TODO
+ */
 define('FIELD_BEHAVIOR_NONE', 0x0001);
 /**
  * TODO
Index: modules/field/field.test
===================================================================
RCS file: /cvs/drupal/drupal/modules/field/field.test,v
retrieving revision 1.17
diff -u -r1.17 field.test
--- modules/field/field.test	3 May 2009 09:49:32 -0000	1.17
+++ modules/field/field.test	10 May 2009 22:58:49 -0000
@@ -65,6 +65,7 @@
   function testFieldAttachSaveLoad() {
     $entity_type = 'test_entity';
     $values = array();
+    $language = FIELD_LANGUAGE_NEUTRAL;
 
     // TODO : test empty values filtering and "compression" (store consecutive deltas).
 
@@ -78,12 +79,12 @@
       $current_revision = $revision_id;
       // If this is the first revision do an insert.
       if (!$revision_id) {
-        $revision[$revision_id]->{$this->field_name} = $values[$revision_id];
+        $revision[$revision_id]->{$this->field_name}[$language] = $values[$revision_id];
         field_attach_insert($entity_type, $revision[$revision_id]);
       }
       else {
         // Otherwise do an update.
-        $revision[$revision_id]->{$this->field_name} = $values[$revision_id];
+        $revision[$revision_id]->{$this->field_name}[$language] = $values[$revision_id];
         field_attach_update($entity_type, $revision[$revision_id]);
       }
     }
@@ -92,10 +93,10 @@
     $entity = field_test_create_stub_entity(0, 0, $this->instance['bundle']);
     field_attach_load($entity_type, array(0 => $entity));
     // Number of values per field loaded equals the field cardinality.
-    $this->assertEqual(count($entity->{$this->field_name}), $this->field['cardinality'], t('Currrent revision: expected number of values'));
+    $this->assertEqual(count($entity->{$this->field_name}[$language]), $this->field['cardinality'], t('Current revision: expected number of values'));
     for ($delta = 0; $delta < $this->field['cardinality']; $delta++) {
       // The field value loaded matches the one inserted or updated.
-      $this->assertEqual($entity->{$this->field_name}[$delta]['value'] , $values[$current_revision][$delta]['value'], t('Currrent revision: expected value %delta was found.', array('%delta' => $delta)));
+      $this->assertEqual($entity->{$this->field_name}[$language][$delta]['value'] , $values[$current_revision][$delta]['value'], t('Current revision: expected value %delta was found.', array('%delta' => $delta)));
     }
 
     // Confirm each revision loads the correct data.
@@ -103,10 +104,10 @@
       $entity = field_test_create_stub_entity(0, $revision_id, $this->instance['bundle']);
       field_attach_load_revision($entity_type, array(0 => $entity));
       // Number of values per field loaded equals the field cardinality.
-      $this->assertEqual(count($entity->{$this->field_name}), $this->field['cardinality'], t('Revision %revision_id: expected number of values.', array('%revision_id' => $revision_id)));
+      $this->assertEqual(count($entity->{$this->field_name}[$language]), $this->field['cardinality'], t('Revision %revision_id: expected number of values.', array('%revision_id' => $revision_id)));
       for ($delta = 0; $delta < $this->field['cardinality']; $delta++) {
         // The field value loaded matches the one inserted or updated.
-        $this->assertEqual($entity->{$this->field_name}[$delta]['value'], $values[$revision_id][$delta]['value'], t('Revision %revision_id: expected value %delta was found.', array('%revision_id' => $revision_id, '%delta' => $delta)));
+        $this->assertEqual($entity->{$this->field_name}[$language][$delta]['value'], $values[$revision_id][$delta]['value'], t('Revision %revision_id: expected value %delta was found.', array('%revision_id' => $revision_id, '%delta' => $delta)));
       }
     }
   }
@@ -117,6 +118,7 @@
   function testFieldAttachSaveMissingData() {
     $entity_type = 'test_entity';
     $entity_init = field_test_create_stub_entity();
+    $language = FIELD_LANGUAGE_NEUTRAL;
 
     // Insert: Field is missing.
     $entity = clone($entity_init);
@@ -129,23 +131,23 @@
     // Insert: Field is NULL.
     field_cache_clear();
     $entity = clone($entity_init);
-    $entity->{$this->field_name} = NULL;
+    $entity->{$this->field_name}[$language] = NULL;
     field_attach_insert($entity_type, $entity);
 
     $entity = clone($entity_init);
     field_attach_load($entity_type, array($entity->ftid => $entity));
-    $this->assertTrue(empty($entity->{$this->field_name}), t('Insert: NULL field results in no value saved'));
+    $this->assertTrue(empty($entity->{$this->field_name}[$language]), t('Insert: NULL field results in no value saved'));
 
     // Add some real data.
     field_cache_clear();
     $entity = clone($entity_init);
     $values = array(0 => array('value' => mt_rand(1, 127)));
-    $entity->{$this->field_name} = $values;
+    $entity->{$this->field_name}[$language] = $values;
     field_attach_insert($entity_type, $entity);
 
     $entity = clone($entity_init);
     field_attach_load($entity_type, array($entity->ftid => $entity));
-    $this->assertEqual($entity->{$this->field_name}, $values, t('Field data saved'));
+    $this->assertEqual($entity->{$this->field_name}[$language], $values, t('Field data saved'));
 
     // Update: Field is missing. Data should survive.
     field_cache_clear();
@@ -154,17 +156,17 @@
 
     $entity = clone($entity_init);
     field_attach_load($entity_type, array($entity->ftid => $entity));
-    $this->assertEqual($entity->{$this->field_name}, $values, t('Update: missing field leaves existing values in place'));
+    $this->assertEqual($entity->{$this->field_name}[$language], $values, t('Update: missing field leaves existing values in place'));
 
     // Update: Field is NULL. Data should be wiped.
     field_cache_clear();
     $entity = clone($entity_init);
-    $entity->{$this->field_name} = NULL;
+    $entity->{$this->field_name}[$language] = NULL;
     field_attach_update($entity_type, $entity);
 
     $entity = clone($entity_init);
     field_attach_load($entity_type, array($entity->ftid => $entity));
-    $this->assertTrue(empty($entity->{$this->field_name}), t('Update: NULL field removes existing values'));
+    $this->assertTrue(empty($entity->{$this->field_name}[$language]), t('Update: NULL field removes existing values'));
   }
 
   /**
@@ -177,15 +179,16 @@
 
     $entity_type = 'test_entity';
     $entity_init = field_test_create_stub_entity();
+    $language = FIELD_LANGUAGE_NEUTRAL;
 
     // Insert: Field is NULL.
     $entity = clone($entity_init);
-    $entity->{$this->field_name} = NULL;
+    $entity->{$this->field_name}[$language] = NULL;
     field_attach_insert($entity_type, $entity);
 
     $entity = clone($entity_init);
     field_attach_load($entity_type, array($entity->ftid => $entity));
-    $this->assertTrue(empty($entity->{$this->field_name}), t('Insert: NULL field results in no value saved'));
+    $this->assertTrue(empty($entity->{$this->field_name}[$language]), t('Insert: NULL field results in no value saved'));
 
     // Insert: Field is missing.
     field_cache_clear();
@@ -195,19 +198,20 @@
     $entity = clone($entity_init);
     field_attach_load($entity_type, array($entity->ftid => $entity));
     $values = field_test_default_value($entity_type, $entity, $this->field, $this->instance);
-    $this->assertEqual($entity->{$this->field_name}, $values, t('Insert: missing field results in default value saved'));
+    $this->assertEqual($entity->{$this->field_name}[$language], $values, t('Insert: missing field results in default value saved'));
   }
 
   function testFieldAttachViewAndPreprocess() {
     $entity_type = 'test_entity';
     $entity = field_test_create_stub_entity(0, 0, $this->instance['bundle']);
+    $language = FIELD_LANGUAGE_NEUTRAL;
 
     // Populate values to be displayed.
     $values = array();
     for ($delta = 0; $delta < $this->field['cardinality']; $delta++) {
       $values[$delta]['value'] = mt_rand(1, 127);
     }
-    $entity->{$this->field_name} = $values;
+    $entity->{$this->field_name}[$language] = $values;
 
     // Simple formatter, label displayed.
     $formatter_setting = $this->randomName();
@@ -225,15 +229,15 @@
     $output = drupal_render($entity->content);
     $variables = field_attach_preprocess($entity_type, $entity);
     $variable = $this->instance['field_name'] . '_rendered';
-    $this->assertTrue(isset($variables[$variable]), "Variable $variable is available in templates.");
+    $this->assertTrue(isset($variables[$language][$variable]), "Variable $variable is available in templates.");
     $this->content = $output;
     $this->assertRaw($this->instance['label'], "Label is displayed.");
-    $this->content = $variables[$variable];
+    $this->content = $variables[$language][$variable];
     $this->assertRaw($this->instance['label'], "Label is displayed (template variable).");
     foreach ($values as $delta => $value) {
       $this->content = $output;
       $this->assertRaw("$formatter_setting|{$value['value']}", "Value $delta is displayed, formatter settings are applied.");
-      $this->content = $variables[$variable];
+      $this->content = $variables[$language][$variable];
       $this->assertRaw("$formatter_setting|{$value['value']}", "Value $delta is displayed, formatter settings are applied (template variable).");
     }
 
@@ -245,7 +249,7 @@
     $variables = field_attach_preprocess($entity_type, $entity);
     $this->content = $output;
     $this->assertNoRaw($this->instance['label'], "Hidden label: label is not displayed.");
-    $this->content = $variables[$variable];
+    $this->content = $variables[$language][$variable];
     $this->assertNoRaw($this->instance['label'], "Hidden label: label is not displayed (template variable).");
 
     // Field hidden.
@@ -260,7 +264,7 @@
     $entity->content = field_attach_view($entity_type, $entity);
     $output = drupal_render($entity->content);
     $variables = field_attach_preprocess($entity_type, $entity);
-    $this->assertTrue(isset($variables[$variable]), "Hidden field: variable $variable is available in templates.");
+    $this->assertTrue(isset($variables[$language][$variable]), "Hidden field: variable $variable is available in templates.");
     $this->content = $output;
     $this->assertNoRaw($this->instance['label'], "Hidden field: label is not displayed.");
     foreach ($values as $delta => $value) {
@@ -288,7 +292,7 @@
     }
     $this->content = $output;
     $this->assertRaw($display, "Multiple formatter: all values are displayed, formatter settings are applied.");
-    $this->content = $variables[$variable];
+    $this->content = $variables[$language][$variable];
     $this->assertRaw($display, "Multiple formatter: all values are displayed, formatter settings are applied (template variable).");
 
     // TODO:
@@ -299,30 +303,31 @@
   function testFieldAttachDelete() {
     $entity_type = 'test_entity';
     $rev[0] = field_test_create_stub_entity(0, 0, $this->instance['bundle']);
+    $language = FIELD_LANGUAGE_NEUTRAL;
 
     // Create revision 0
     $values = array();
     for ($delta = 0; $delta < $this->field['cardinality']; $delta++) {
       $values[$delta]['value'] = mt_rand(1, 127);
     }
-    $rev[0]->{$this->field_name} = $values;
+    $rev[0]->{$this->field_name}[$language] = $values;
     field_attach_insert($entity_type, $rev[0]);
 
     // Create revision 1
     $rev[1] = field_test_create_stub_entity(0, 1, $this->instance['bundle']);
-    $rev[1]->{$this->field_name} = $values;
+    $rev[1]->{$this->field_name}[$language] = $values;
     field_attach_update($entity_type, $rev[1]);
 
     // Create revision 2
     $rev[2] = field_test_create_stub_entity(0, 2, $this->instance['bundle']);
-    $rev[2]->{$this->field_name} = $values;
+    $rev[2]->{$this->field_name}[$language] = $values;
     field_attach_update($entity_type, $rev[2]);
 
     // Confirm each revision loads
     foreach (array_keys($rev) as $vid) {
       $read = field_test_create_stub_entity(0, $vid, $this->instance['bundle']);
       field_attach_load_revision($entity_type, array(0 => $read));
-      $this->assertEqual(count($read->{$this->field_name}), $this->field['cardinality'], "The test object revision $vid has {$this->field['cardinality']} values.");
+      $this->assertEqual(count($read->{$this->field_name}[$language]), $this->field['cardinality'], "The test object revision $vid has {$this->field['cardinality']} values.");
     }
 
     // Delete revision 1, confirm the other two still load.
@@ -330,13 +335,13 @@
     foreach (array(0, 2) as $vid) {
       $read = field_test_create_stub_entity(0, $vid, $this->instance['bundle']);
       field_attach_load_revision($entity_type, array(0 => $read));
-      $this->assertEqual(count($read->{$this->field_name}), $this->field['cardinality'], "The test object revision $vid has {$this->field['cardinality']} values.");
+      $this->assertEqual(count($read->{$this->field_name}[$language]), $this->field['cardinality'], "The test object revision $vid has {$this->field['cardinality']} values.");
     }
 
     // Confirm the current revision still loads
     $read = field_test_create_stub_entity(0, 2, $this->instance['bundle']);
     field_attach_load($entity_type, array(0 => $read));
-    $this->assertEqual(count($read->{$this->field_name}), $this->field['cardinality'], "The test object current revision has {$this->field['cardinality']} values.");
+    $this->assertEqual(count($read->{$this->field_name}[$language]), $this->field['cardinality'], "The test object current revision has {$this->field['cardinality']} values.");
 
     // Delete all field data, confirm nothing loads
     field_attach_delete($entity_type, $rev[2]);
@@ -347,7 +352,7 @@
     }
     $read = field_test_create_stub_entity(0, 2, $this->instance['bundle']);
     field_attach_load($entity_type, array(0 => $read));
-      $this->assertIdentical($read->{$this->field_name}, array(), "The test object current revision is deleted.");
+    $this->assertIdentical($read->{$this->field_name}, array(), "The test object current revision is deleted.");
   }
 
   function testFieldAttachCreateRenameBundle() {
@@ -355,6 +360,7 @@
     // hook_fieldable_info() is consistent.
     $new_bundle = 'test_bundle_' . drupal_strtolower($this->randomName());
     field_test_create_bundle($new_bundle, $this->randomName());
+    $language = FIELD_LANGUAGE_NEUTRAL;
 
     // Add an instance to that bundle.
     $this->instance['bundle'] = $new_bundle;
@@ -366,14 +372,14 @@
     for ($delta = 0; $delta < $this->field['cardinality']; $delta++) {
       $values[$delta]['value'] = mt_rand(1, 127);
     }
-    $entity->{$this->field_name} = $values;
+    $entity->{$this->field_name}[$language] = $values;
     $entity_type = 'test_entity';
     field_attach_insert($entity_type, $entity);
 
     // Verify the field data is present on load.
     $entity = field_test_create_stub_entity(0, 0, $this->instance['bundle']);
     field_attach_load($entity_type, array(0 => $entity));
-    $this->assertEqual(count($entity->{$this->field_name}), $this->field['cardinality'], "Data are retrieved for the new bundle");
+    $this->assertEqual(count($entity->{$this->field_name}[$language]), $this->field['cardinality'], "Data are retrieved for the new bundle");
 
     // Rename the bundle. This has to be initiated by the module so that its
     // hook_fieldable_info() is consistent.
@@ -387,7 +393,7 @@
     // Verify the field data is present on load.
     $entity = field_test_create_stub_entity(0, 0, $this->instance['bundle']);
     field_attach_load($entity_type, array(0 => $entity));
-    $this->assertEqual(count($entity->{$this->field_name}), $this->field['cardinality'], "Bundle name has been updated in the field storage");
+    $this->assertEqual(count($entity->{$this->field_name}[$language]), $this->field['cardinality'], "Bundle name has been updated in the field storage");
   }
 
   function testFieldAttachDeleteBundle() {
@@ -423,16 +429,17 @@
     for ($delta = 0; $delta < $this->field['cardinality']; $delta++) {
       $values[$delta]['value'] = mt_rand(1, 127);
     }
-    $entity->{$this->field_name} = $values;
-    $entity->{$field_name} = array(0 => array('value' => 99));
+    $language = FIELD_LANGUAGE_NEUTRAL;
+    $entity->{$this->field_name}[$language] = $values;
+    $entity->{$field_name}[$language] = array(0 => array('value' => 99));
     $entity_type = 'test_entity';
     field_attach_insert($entity_type, $entity);
 
     // Verify the fields are present on load
     $entity = field_test_create_stub_entity(0, 0, $this->instance['bundle']);
     field_attach_load($entity_type, array(0 => $entity));
-    $this->assertEqual(count($entity->{$this->field_name}), 4, "First field got loaded");
-    $this->assertEqual(count($entity->{$field_name}), 1, "Second field got loaded");
+    $this->assertEqual(count($entity->{$this->field_name}[$language]), 4, "First field got loaded");
+    $this->assertEqual(count($entity->{$field_name}[$language]), 1, "Second field got loaded");
 
     // Delete the bundle. This has to be initiated by the module so that its
     // hook_fieldable_info() is consistent.
@@ -441,8 +448,8 @@
     // Verify no data gets loaded
     $entity = field_test_create_stub_entity(0, 0, $this->instance['bundle']);
     field_attach_load($entity_type, array(0 => $entity));
-    $this->assertFalse(isset($entity->{$this->field_name}), "No data for first field");
-    $this->assertFalse(isset($entity->{$field_name}), "No data for second field");
+    $this->assertFalse(isset($entity->{$this->field_name}[$language]), "No data for first field");
+    $this->assertFalse(isset($entity->{$field_name}[$language]), "No data for second field");
 
     // Verify that the instances are gone
     $this->assertFalse(field_read_instance($this->field_name, $this->instance['bundle']), "First field is deleted");
@@ -451,12 +458,13 @@
 
   function testFieldAttachCache() {
     // Create a revision
+    $language = FIELD_LANGUAGE_NEUTRAL;
     $entity = field_test_create_stub_entity(0, 0, $this->instance['bundle']);
     $values = array();
     for ($delta = 0; $delta < $this->field['cardinality']; $delta++) {
       $values[$delta]['value'] = mt_rand(1, 127);
     }
-    $entity->{$this->field_name} = $values;
+    $entity->{$this->field_name}[$language] = $values;
 
     $noncached_type = 'test_entity';
     $cached_type = 'test_cacheable_entity';
@@ -488,7 +496,7 @@
     // Load, and confirm cache entry
     field_attach_load($cached_type, array(0 => $entity));
     $cache = cache_get($cid, 'cache_field');
-    $this->assertEqual($cache->data[$this->field_name], $values, 'Cached: correct cache entry on load');
+    $this->assertEqual($cache->data[$this->field_name][$language], $values, 'Cached: correct cache entry on load');
 
     // Delete, and confirm no cache entry
     field_attach_delete($cached_type, $entity);
@@ -500,6 +508,7 @@
   function testFieldAttachValidate() {
     $entity_type = 'test_entity';
     $entity = field_test_create_stub_entity(0, 0, $this->instance['bundle']);
+    $language = FIELD_LANGUAGE_NEUTRAL;
 
     // Set up values to generate errors
     $values = array();
@@ -509,7 +518,7 @@
     }
     // Arrange for item 1 not to generate an error
     $values[1]['value'] = 1;
-    $entity->{$this->field_name} = $values;
+    $entity->{$this->field_name}[$language] = $values;
 
     try {
       field_attach_validate($entity_type, $entity);
@@ -540,10 +549,11 @@
     $form = $form_state = array();
     field_attach_form($entity_type, $entity, $form, $form_state);
 
-    $this->assertEqual($form[$this->field_name]['#title'], $this->instance['label'], "Form title is {$this->instance['label']}");
+    $language = FIELD_LANGUAGE_NEUTRAL;
+    $this->assertEqual($form['field_translations'][$language][$this->field_name]['#title'], $this->instance['label'], "Form title is {$this->instance['label']}");
     for ($delta = 0; $delta < $this->field['cardinality']; $delta++) {
       // field_test_widget uses 'textfield'
-      $this->assertEqual($form[$this->field_name][$delta]['value']['#type'], 'textfield', "Form delta $delta widget is textfield");
+      $this->assertEqual($form['field_translations'][$language][$this->field_name][$delta]['value']['#type'], 'textfield', "Form delta $delta widget is textfield");
     }
   }
 
@@ -570,7 +580,8 @@
     // Leave an empty value. 'field_test' fields are empty if empty().
     $values[1]['value'] = 0;
 
-    $form_state['values'] = array($this->field_name => $values);
+    $language = FIELD_LANGUAGE_NEUTRAL;
+    $form_state['values'] = array('field_translations' => array($language => array($this->field_name => $values)));
     field_attach_submit($entity_type, $entity, $form, $form_state);
 
     asort($weights);
@@ -580,7 +591,115 @@
         $expected_values[] = array('value' => $values[$key]['value']);
       }
     }
-    $this->assertIdentical($entity->{$this->field_name}, $expected_values, 'Submit filters empty values');
+    $this->assertIdentical($entity->{$this->field_name}[$language], $expected_values, 'Submit filters empty values');
+  }
+}
+
+/**
+ * Unit test class for the multilanguage fields logic.
+ *
+ * The following tests will check the multilanguage logic of 
+ * _field_invoke and that only the correct values are returned 
+ * by _field_available_languages.
+ */
+class FieldTranslationsTestCase extends DrupalWebTestCase {
+  public static function getInfo() {
+    return array(
+      'name'  => t('Field translations tests'),
+      'description'  => t("Test multilanguage fields logic."),
+      'group' => t('Field')
+    );
+  }
+
+  function setUp() {
+    parent::setUp('field_test', 'locale');
+
+    $this->field_name = drupal_strtolower($this->randomName() . '_field_name');
+    
+    $this->field = array(
+      'field_name' => $this->field_name,
+      'type' => 'test_field',
+      'cardinality' => 4,
+      'translatable' => TRUE,
+    );
+    field_create_field($this->field);
+    
+    $this->instance = array(
+      'field_name' => $this->field_name,
+      'bundle' => 'test_bundle',
+      'label' => $this->randomName() . '_label',
+      'description' => $this->randomName() . '_description',
+      'weight' => mt_rand(0, 127),
+      'settings' => array(
+        'test_instance_setting' => $this->randomName(),
+      ),
+      'widget' => array(
+        'type' => 'test_field_widget',
+        'label' => 'Test Field',
+        'settings' => array(
+          'test_widget_setting' => $this->randomName(),
+        )
+      )
+    );
+    field_create_instance($this->instance);
+    
+    require_once DRUPAL_ROOT . '/includes/locale.inc';
+    for ($i = 0; $i < 3; ++$i) {
+      locale_add_language('l'.$i, $this->randomString(), $this->randomString());
+    }
+  }
+
+  /**
+   * Check that that only the correct values are returned by _field_available_languages.
+   */
+  function testFieldAvailableLanguages() {
+    // Test hook_field_languages invocation on a translatable field.
+    $enabled_languages = array_keys(language_list());
+    $available_languages = _field_available_languages($this->field, $this->instance); 
+    foreach ($available_languages as $language) {
+      $this->assertTrue(in_array($language, $enabled_languages), t('%language is an enabled language', array('%language' => $language)));
+    }
+    $this->assertTrue(count($available_languages) == count($enabled_languages) - 1, t('An enabled language was successfully made unavailable'));
+    
+    // Test _field_available_languages behavior for untranslatable fields.
+    $this->field['translatable'] = FALSE;
+    $this->field_name = $this->field['field_name'] = $this->instance['field_name'] = 'ut_test_field';
+    $available_languages = _field_available_languages($this->field, $this->instance);
+    $this->assertTrue(count($available_languages) == 1 && $available_languages[0] === FIELD_LANGUAGE_NEUTRAL, t('For untranslatable fields only neutral language is available'));
+  }
+
+  /**
+   * Test the multilanguage logic of _field_invoke.
+   */
+  function testFieldInvoke() {
+    $entity_type = 'test_entity';
+    $entity = field_test_create_stub_entity(0, 0, $this->instance['bundle']);
+    
+    // Populate some extra languages to check if _field_invoke correctly uses
+    // the result of _field_available_languages
+    $values = array();
+    $extra_languages = mt_rand(1, 4);
+    $languages = $available_languages = _field_available_languages($this->field, $this->instance);
+    for ($i = 0; $i < $extra_languages; ++$i) {
+      $languages[] = $this->randomString(2);
+    }
+    
+    // For each given language provide some random values.
+    foreach ($languages as $language) {
+      for ($delta = 0; $delta < $this->field['cardinality']; $delta++) {
+        $values[$language][$delta]['value'] = mt_rand(1, 127);
+      }
+    }
+    $entity->{$this->field_name} = $values;
+    
+    $results = _field_invoke('test_op', $entity_type, $entity);
+    foreach ($results as $language => $result) {
+      $sign = md5(serialize(array($entity_type, $entity, $this->field_name, $language, $values[$language])));
+      // Check if the parameters passed to _field_invoke were correctly forwarded to the callback function
+      // and if its result has been correctly stored by language in the returned data structure. 
+      $this->assertEqual($sign, $result[0], t('The result for %language is correctly stored', array('%language' => $language)));
+    }
+    $this->assertEqual(count($results), count($available_languages), t('No unavailable language has been processed'));
   }
 }
 
Index: modules/field/field.default.inc
===================================================================
RCS file: /cvs/drupal/drupal/modules/field/field.default.inc,v
retrieving revision 1.6
diff -u -r1.6 field.default.inc
--- modules/field/field.default.inc	1 May 2009 15:28:13 -0000	1.6
+++ modules/field/field.default.inc	10 May 2009 22:58:47 -0000
@@ -11,21 +11,21 @@
  * the corresponding field_attach_[operation]() function.
  */
 
-function field_default_extract_form_values($obj_type, $object, $field, $instance, &$items, $form, &$form_state) {
+function field_default_extract_form_values($obj_type, $object, $field, $instance, $language, &$items, $form, &$form_state) {
   $field_name = $field['field_name'];
 
-  if (isset($form_state['values'][$field_name])) {
-    $items = $form_state['values'][$field_name];
+  if (isset($form_state['values']['field_translations'][$language][$field_name])) {
+    $items = $form_state['values']['field_translations'][$language][$field_name];
     // Remove the 'value' of the 'add more' button.
     unset($items[$field_name . '_add_more']);
   }
 }
 
-function field_default_validate($obj_type, $object, $field, $instance, $items) {
+function field_default_validate($obj_type, $object, $field, $instance, $language, $items) {
   // TODO: here we could validate that required fields are filled in (for programmatic save)
 }
 
-function field_default_submit($obj_type, &$object, $field, $instance, &$items, $form, &$form_state) {
+function field_default_submit($obj_type, &$object, $field, $instance, $language, &$items, $form, &$form_state) {
   $field_name = $field['field_name'];
 
   // TODO: should me move what's below to __extract_form_values ?
@@ -46,7 +46,7 @@
  * This can happen with programmatic saves, or on form-based creation where
  * the current user doesn't have 'edit' permission for the field.
  */
-function field_default_insert($obj_type, &$object, $field, $instance, &$items) {
+function field_default_insert($obj_type, &$object, $field, $instance, $language, &$items) {
   // _field_invoke() populates $items with an empty array if the $object has no
   // entry for the field, so we check on the $object itself.
   if (!property_exists($object, $field['field_name']) && !empty($instance['default_value_function'])) {
@@ -112,7 +112,7 @@
  *     ),
  *   );
  */
-function field_default_view($obj_type, $object, $field, $instance, $items, $teaser) {
+function field_default_view($obj_type, $object, $field, $instance, $language, $items, $teaser) {
   list($id, $vid, $bundle) = field_attach_extract_ids($obj_type, $object);
 
   $addition = array();
@@ -242,13 +242,14 @@
   }
 }
 
-function field_default_preprocess($obj_type, $object, $field, $instance, &$items) {
+function field_default_preprocess($obj_type, $object, $field, $instance, $language, &$items) {
   return array(
-    $field['field_name'] . '_rendered' => isset($object->content[$field['field_name']]['#children']) ? $object->content[$field['field_name']]['#children'] : '',
+    $field['field_name'] . '_rendered' => isset($object->content['field_translations'][$language][$field['field_name']]['#children']) ?
+      $object->content['field_translations'][$language][$field['field_name']]['#children'] : '',
   );
 }
 
-function field_default_prepare_translation($obj_type, $object, $field, $instance, &$items) {
+function field_default_prepare_translation($obj_type, $object, $field, $instance, $language, &$items) {
   $addition = array();
   if (isset($object->translation_source->$field['field_name'])) {
     $addition[$field['field_name']] = $object->translation_source->$field['field_name'];
Index: modules/field/field.crud.inc
===================================================================
RCS file: /cvs/drupal/drupal/modules/field/field.crud.inc,v
retrieving revision 1.11
diff -u -r1.11 field.crud.inc
--- modules/field/field.crud.inc	30 Apr 2009 14:40:03 -0000	1.11
+++ modules/field/field.crud.inc	10 May 2009 22:58:47 -0000
@@ -46,6 +46,8 @@
  * - cardinality (integer)
  *     The number of values the field can hold. Legal values are any
  *     positive integer or FIELD_CARDINALITY_UNLIMITED.
+ * - translatable (integer)
+ *     Whether the field is translatable
  * - locked (integer)
  *     TODO: undefined.
  * - module (string, read-only)
@@ -212,6 +214,7 @@
 
   $field += array(
     'cardinality' => 1,
+    'translatable' => FALSE,
     'locked' => FALSE,
     'settings' => array(),
   );
Index: modules/field/modules/text/text.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/field/modules/text/text.module,v
retrieving revision 1.6
diff -u -r1.6 text.module
--- modules/field/modules/text/text.module	12 Apr 2009 02:18:51 -0000	1.6
+++ modules/field/modules/text/text.module	10 May 2009 22:58:50 -0000
@@ -92,7 +92,7 @@
  * Possible error codes:
  * - 'text_max_length': The value exceeds the maximum length.
  */
-function text_field_validate($obj_type, $object, $field, $instance, $items, &$errors) {
+function text_field_validate($obj_type, $object, $field, $instance, $language, $items, &$errors) {
   foreach ($items as $delta => $item) {
     if (!empty($item['value'])) {
       if (!empty($field['settings']['max_length']) && drupal_strlen($item['value']) > $field['settings']['max_length']) {
@@ -105,7 +105,7 @@
   }
 }
 
-function text_field_sanitize($obj_type, $object, $field, $instance, &$items) {
+function text_field_sanitize($obj_type, $object, $field, $instance, $language, &$items) {
   global $language;
   foreach ($items as $delta => $item) {
     // TODO D7 : this code is really node-related.
Index: modules/field/modules/text/text.test
===================================================================
RCS file: /cvs/drupal/drupal/modules/field/modules/text/text.test,v
retrieving revision 1.6
diff -u -r1.6 text.test
--- modules/field/modules/text/text.test	29 Apr 2009 12:08:28 -0000	1.6
+++ modules/field/modules/text/text.test	10 May 2009 22:58:50 -0000
@@ -50,8 +50,9 @@
     field_create_instance($this->instance);
     // Test valid and invalid values with field_attach_validate().
     $entity = field_test_create_stub_entity(0, 0, FIELD_TEST_BUNDLE);
+    $language = FIELD_LANGUAGE_NEUTRAL;
     for ($i = 0; $i <= $max_length + 2; $i++) {
-      $entity->{$this->field['field_name']}[0]['value'] = str_repeat('x', $i);
+      $entity->{$this->field['field_name']}[$language][0]['value'] = str_repeat('x', $i);
       try {
         field_attach_validate('test_entity', $entity);
         $this->assertTrue($i <= $max_length, "Length $i does not cause validation error when max_length is $max_length");
Index: modules/field/modules/field_sql_storage/field_sql_storage.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/field/modules/field_sql_storage/field_sql_storage.module,v
retrieving revision 1.6
diff -u -r1.6 field_sql_storage.module
--- modules/field/modules/field_sql_storage/field_sql_storage.module	30 Mar 2009 03:44:55 -0000	1.6
+++ modules/field/modules/field_sql_storage/field_sql_storage.module	10 May 2009 22:58:49 -0000
@@ -128,8 +128,16 @@
         'not null' => TRUE,
         'description' => 'The sequence number for this data item, used for multi-value fields',
       ),
+      // @todo Consider an integer field for 'language'.
+      'language' => array(
+        'type' => 'varchar',
+        'length' => 32,
+        'not null' => TRUE,
+        'default' => '',
+        'description' => 'The language for this data item.',
+      ),
     ),
-    'primary key' => array('etid', 'entity_id', 'deleted', 'delta'),
+    'primary key' => array('etid', 'entity_id', 'deleted', 'delta', 'language'),
     // TODO : index on 'bundle'
   );
 
@@ -144,7 +152,7 @@
   $revision = $current;
   $revision['description'] = 'Revision archive storage for field ' . $field['field_name'];
   $revision['revision_id']['description'] = 'The entity revision id this data is attached to';
-  $revision['primary key'] = array('etid', 'revision_id', 'deleted', 'delta');
+  $revision['primary key'] = array('etid', 'revision_id', 'deleted', 'delta', 'language');
 
   return array(
     _field_sql_storage_tablename($field['field_name']) => $current,
@@ -187,7 +195,7 @@
     list($id, $vid, $bundle) = field_attach_extract_ids($obj_type, $obj);
     foreach (field_info_instances($bundle) as $instance) {
       $field_ids[$instance['field_name']][] = $load_current ? $id : $vid;
-      $delta_count[$id][$instance['field_name']] = 0;
+      $delta_count[$id][$instance['field_name']] = array();
     }
   }
 
@@ -209,7 +217,11 @@
       ->execute();
 
     foreach ($results as $row) {
-      if ($field['cardinality'] == FIELD_CARDINALITY_UNLIMITED || $delta_count[$row->entity_id][$field_name] < $field['cardinality']) {
+      if (!isset($delta_count[$row->entity_id][$field_name][$row->language])) {
+        $delta_count[$row->entity_id][$field_name][$row->language] = 0;
+      }
+
+      if ($field['cardinality'] == FIELD_CARDINALITY_UNLIMITED || $delta_count[$row->entity_id][$field_name][$row->language] < $field['cardinality']) {
         $item = array();
         // For each column declared by the field, populate the item
         // from the prefixed database column.
@@ -217,9 +229,9 @@
           $item[$column] = $row->{_field_sql_storage_columnname($field_name, $column)};
         }
 
-        // Add the item to the field values for the entity.
-        $additions[$row->entity_id][$field_name][] = $item;
-        $delta_count[$row->entity_id][$field_name]++;
+        // Add the item to the field values for the entity according to its language.
+        $additions[$row->entity_id][$field_name][$row->language][$row->delta] = $item;
+        $delta_count[$row->entity_id][$field_name][$row->language]++;
       }
     }
   }
@@ -244,58 +256,59 @@
     $revision_name = _field_sql_storage_revision_tablename($field_name);
     $field = field_read_field($field_name);
 
-    // Leave the field untouched if $object comes with no $field_name property.
-    // Empty the field if $object->$field_name is NULL or an empty array.
-
-    // Function property_exists() is slower, so we catch the more frequent cases
-    // where it's an empty array with the faster isset().
-    if (isset($object->$field_name) || property_exists($object, $field_name)) {
+    // Leave the field untouched if $object comes with an empty $field_name property.
+    // Empty the field translations if $object->$field_name[$language] is NULL or an empty array.
+    if (isset($object->$field_name) && is_array($object->$field_name) && count($object->$field_name) > 0) {
       // Delete and insert, rather than update, in case a value was added.
       if ($op == FIELD_STORAGE_UPDATE) {
-        db_delete($table_name)->condition('etid', $etid)->condition('entity_id', $id)->execute();
+        $languages = array_keys($object->$field_name);
+        db_delete($table_name)->condition('etid', $etid)->condition('entity_id', $id)->condition('language', $languages, 'IN')->execute();
         if (isset($vid)) {
-          db_delete($revision_name)->condition('etid', $etid)->condition('entity_id', $id)->condition('revision_id', $vid)->execute();
+          db_delete($revision_name)->condition('etid', $etid)->condition('entity_id', $id)->condition('revision_id', $vid)->condition('language', $languages, 'IN')->execute();
         }
       }
 
-      if ($object->$field_name) {
-        // Prepare the multi-insert query.
-        $columns = array('etid', 'entity_id', 'revision_id', 'bundle', 'delta');
-        foreach ($field['columns'] as $column => $attributes) {
-          $columns[] = _field_sql_storage_columnname($field_name, $column);
-        }
-        $query = db_insert($table_name)->fields($columns);
-        if (isset($vid)) {
-          $revision_query = db_insert($revision_name)->fields($columns);
-        }
-
-        $delta_count = 0;
-        foreach ($object->$field_name as $delta => $item) {
-          $record = array(
-            'etid' => $etid,
-            'entity_id' => $id,
-            'revision_id' => $vid,
-            'bundle' => $bundle,
-            'delta' => $delta,
-          );
-          foreach ($field['columns'] as $column => $attributes) {
-            $record[_field_sql_storage_columnname($field_name, $column)] = isset($item[$column]) ? $item[$column] : NULL;
-          }
-          $query->values($record);
-          if (isset($vid)) {
-            $revision_query->values($record);
-          }
+      // Prepare the multi-insert query.
+      $columns = array('etid', 'entity_id', 'revision_id', 'bundle', 'delta', 'language');
+      foreach ($field['columns'] as $column => $attributes) {
+        $columns[] = _field_sql_storage_columnname($field_name, $column);
+      }
+      $query = db_insert($table_name)->fields($columns);
+      if (isset($vid)) {
+        $revision_query = db_insert($revision_name)->fields($columns);
+      }
 
-          if ($field['cardinality'] != FIELD_CARDINALITY_UNLIMITED && ++$delta_count == $field['cardinality']) {
-            break;
+      foreach ($object->$field_name as $language => $items) {
+        if ($items) {
+          $delta_count = 0;
+          foreach ($items as $delta => $item) {
+            $record = array(
+              'etid' => $etid,
+              'entity_id' => $id,
+              'revision_id' => $vid,
+              'bundle' => $bundle,
+              'delta' => $delta,
+              'language' => $language,
+            );
+            foreach ($field['columns'] as $column => $attributes) {
+              $record[_field_sql_storage_columnname($field_name, $column)] = isset($item[$column]) ? $item[$column] : NULL;
+            }
+            $query->values($record);
+            if (isset($vid)) {
+              $revision_query->values($record);
+            }
+
+            if ($field['cardinality'] != FIELD_CARDINALITY_UNLIMITED && ++$delta_count == $field['cardinality']) {
+              break;
+            }
           }
         }
+      }
 
-        // Execute the insert.
-        $query->execute();
-        if (isset($vid)) {
-          $revision_query->execute();
-        }
+      // Execute the insert.
+      $query->execute();
+      if (isset($vid)) {
+        $revision_query->execute();
       }
     }
   }
Index: modules/field/modules/field_sql_storage/field_sql_storage.test
===================================================================
RCS file: /cvs/drupal/drupal/modules/field/modules/field_sql_storage/field_sql_storage.test,v
retrieving revision 1.3
diff -u -r1.3 field_sql_storage.test
--- modules/field/modules/field_sql_storage/field_sql_storage.test	29 Apr 2009 21:33:00 -0000	1.3
+++ modules/field/modules/field_sql_storage/field_sql_storage.test	10 May 2009 22:58:50 -0000
@@ -56,9 +56,10 @@
   function testFieldAttachLoad() {
     $entity_type = 'test_entity';
     $eid = 0;
+    $language = FIELD_LANGUAGE_NEUTRAL;
 
     $etid = _field_sql_storage_etid($entity_type);
-    $columns = array('etid', 'entity_id', 'revision_id', 'delta', $this->field_name . '_value');
+    $columns = array('etid', 'entity_id', 'revision_id', 'delta', 'language', $this->field_name . '_value');
 
     // Insert data for four revisions to the field revisions table
     $query = db_insert($this->revision_table)->fields($columns);
@@ -68,7 +69,7 @@
       for ($delta = 0; $delta <= $this->field['cardinality']; $delta++) {
         $value = mt_rand(1, 127);
         $values[$evid][] = $value;
-        $query->values(array($etid, $eid, $evid, $delta, $value));
+        $query->values(array($etid, $eid, $evid, $delta, $language, $value));
       }
     }
     $query->execute();
@@ -76,7 +77,7 @@
     // Insert data for the "most current revision" into the field table
     $query = db_insert($this->table)->fields($columns);
     foreach ($values[0] as $delta => $value) {
-      $query->values(array($etid, $eid, 0, $delta, $value));
+      $query->values(array($etid, $eid, 0, $delta, $language, $value));
     }
     $query->execute();
 
@@ -85,10 +86,10 @@
     field_attach_load($entity_type, array($eid => $entity));
     foreach ($values[0] as $delta => $value) {
       if ($delta < $this->field['cardinality']) {
-        $this->assertEqual($entity->{$this->field_name}[$delta]['value'], $value, "Value $delta is loaded correctly for current revision");
+        $this->assertEqual($entity->{$this->field_name}[$language][$delta]['value'], $value, "Value $delta is loaded correctly for current revision");
       }
       else {
-        $this->assertFalse(array_key_exists($delta, $entity->{$this->field_name}), "No extraneous value gets loaded for current revision.");
+        $this->assertFalse(array_key_exists($delta, $entity->{$this->field_name}[$language]), "No extraneous value gets loaded for current revision.");
       }
     }
 
@@ -98,10 +99,10 @@
       field_attach_load_revision($entity_type, array($eid => $entity));
       foreach ($values[$evid] as $delta => $value) {
         if ($delta < $this->field['cardinality']) {
-          $this->assertEqual($entity->{$this->field_name}[$delta]['value'], $value, "Value $delta for revision $evid is loaded correctly");
+          $this->assertEqual($entity->{$this->field_name}[$language][$delta]['value'], $value, "Value $delta for revision $evid is loaded correctly");
         }
         else {
-          $this->assertFalse(array_key_exists($delta, $entity->{$this->field_name}), "No extraneous value gets loaded for revision $evid.");
+          $this->assertFalse(array_key_exists($delta, $entity->{$this->field_name}[$language]), "No extraneous value gets loaded for revision $evid.");
         }
       }
     }
@@ -114,6 +115,7 @@
   function testFieldAttachInsertAndUpdate() {
     $entity_type = 'test_entity';
     $entity = field_test_create_stub_entity(0, 0, $this->instance['bundle']);
+    $language = FIELD_LANGUAGE_NEUTRAL;
 
     // Test insert.
     $values = array();
@@ -122,7 +124,7 @@
     for ($delta = 0; $delta <= $this->field['cardinality']; $delta++) {
       $values[$delta]['value'] = mt_rand(1, 127);
     }
-    $entity->{$this->field_name} = $rev_values[0] = $values;
+    $entity->{$this->field_name}[$language] = $rev_values[0] = $values;
     field_attach_insert($entity_type, $entity);
 
     $rows = db_select($this->table, 't')->fields('t')->execute()->fetchAllAssoc('delta', PDO::FETCH_ASSOC);
@@ -142,7 +144,7 @@
     for ($delta = 0; $delta <= $this->field['cardinality']; $delta++) {
       $values[$delta]['value'] = mt_rand(1, 127);
     }
-    $entity->{$this->field_name} = $rev_values[1] = $values;
+    $entity->{$this->field_name}[$language] = $rev_values[1] = $values;
     field_attach_update($entity_type, $entity);
     $rows = db_select($this->table, 't')->fields('t')->execute()->fetchAllAssoc('delta', PDO::FETCH_ASSOC);
     foreach ($values as $delta => $value) {
@@ -170,9 +172,9 @@
     }
     $this->assertTrue(empty($rev_values), "All values for all revisions are stored in revision table {$this->revision_table}");
 
-    // Check that update leaves the field data untouched if $object has no
-    // $field_name key.
-    unset($entity->{$this->field_name});
+    // Check that update leaves the field data untouched if $object->{$field_name} has no
+    // language key.
+    unset($entity->{$this->field_name}[$language]);
     field_attach_update($entity_type, $entity);
     $rows = db_select($this->table, 't')->fields('t')->execute()->fetchAllAssoc('delta', PDO::FETCH_ASSOC);
     foreach ($values as $delta => $value) {
@@ -182,7 +184,7 @@
     }
 
     // Check that update with an empty $object->$field_name empties the field.
-    $entity->{$this->field_name} = NULL;
+    $entity->{$this->field_name}[$language] = NULL;
     field_attach_update($entity_type, $entity);
     $rows = db_select($this->table, 't')->fields('t')->execute()->fetchAllAssoc('delta', PDO::FETCH_ASSOC);
     $this->assertEqual(count($rows), 0, t("Update with an empty field_name entry empties the field."));
@@ -194,6 +196,7 @@
   function testFieldAttachSaveMissingData() {
     $entity_type = 'test_entity';
     $entity = field_test_create_stub_entity(0, 0, $this->instance['bundle']);
+    $language = FIELD_LANGUAGE_NEUTRAL;
 
     // Insert: Field is missing
     field_attach_insert($entity_type, $entity);
@@ -201,25 +204,25 @@
     $this->assertEqual($count, 0, 'Missing field results in no inserts');
 
     // Insert: Field is NULL
-    $entity->{$this->field_name} = NULL;
+    $entity->{$this->field_name}[$language] = NULL;
     field_attach_insert($entity_type, $entity);
     $count = db_result(db_query("SELECT COUNT(*) FROM {{$this->table}}"));
     $this->assertEqual($count, 0, 'NULL field results in no inserts');
 
     // Add some real data
-    $entity->{$this->field_name} = array(0 => array('value' => 1));
+    $entity->{$this->field_name}[$language] = array(0 => array('value' => 1));
     field_attach_insert($entity_type, $entity);
     $count = db_result(db_query("SELECT COUNT(*) FROM {{$this->table}}"));
     $this->assertEqual($count, 1, 'Field data saved');
 
-    // Update: Field is missing. Data should survive.
-    unset($entity->{$this->field_name});
+    // Update: Field translation is missing. Data should survive.
+    unset($entity->{$this->field_name}[$language]);
     field_attach_update($entity_type, $entity);
     $count = db_result(db_query("SELECT COUNT(*) FROM {{$this->table}}"));
     $this->assertEqual($count, 1, 'Missing field leaves data in table');
 
     // Update: Field is NULL. Data should be wiped.
-    $entity->{$this->field_name} = NULL;
+    $entity->{$this->field_name}[$language] = NULL;
     field_attach_update($entity_type, $entity);
     $count = db_result(db_query("SELECT COUNT(*) FROM {{$this->table}}"));
     $this->assertEqual($count, 0, 'NULL field leaves no data in table');
Index: modules/simpletest/tests/field_test.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/simpletest/tests/field_test.module,v
retrieving revision 1.5
diff -u -r1.5 field_test.module
--- modules/simpletest/tests/field_test.module	1 May 2009 19:17:46 -0000	1.5
+++ modules/simpletest/tests/field_test.module	10 May 2009 22:58:51 -0000
@@ -345,7 +345,7 @@
  * Possible error codes:
  * - 'field_test_invalid': The value is invalid.
  */
-function field_test_field_validate($obj_type, $object, $field, $instance, $items, &$errors) {
+function field_test_field_validate($obj_type, $object, $field, $instance, $language, $items, &$errors) {
   foreach ($items as $delta => $item) {
     if ($item['value'] == -1) {
       $errors[$field['field_name']][$delta][] = array(
@@ -359,7 +359,7 @@
 /**
  * Implementation of hook_field_sanitize().
  */
-function field_test_field_sanitize($obj_type, $object, $field, $instance, &$items) {
+function field_test_field_sanitize($obj_type, $object, $field, $instance, $language, &$items) {
   foreach ($items as $delta => $item) {
     $value = check_plain($item['value']);
     $items[$delta]['safe'] = $value;
@@ -430,8 +430,8 @@
  *   holds the field's form values.
  * @param $field
  *   The field structure.
- * @param $insatnce
- *   the insatnce array
+ * @param $instance
+ *   the instance array
  * @param $items
  *   array of default values for this field
  * @param $delta
@@ -530,4 +530,21 @@
  */
 function field_test_default_value($obj_type, $object, $field, $instance) {
   return array(array('value' => 99));
-}
\ No newline at end of file
+}
+
+/**
+ * Generic op to test _field_invoke behavior.
+ */
+function field_test_field_test_op($obj_type, $object, $field, $instance, $language, &$items) {
+  return md5(serialize(array($obj_type, $object, $field['field_name'], $language, $items)));
+}
+
+/**
+ * Implementation of hook_field_languages
+ */
+function field_test_field_languages($field, $instance, &$languages) {
+  // Add an unavailable language.
+  $languages[] = 'xx';
+  // Remove an available language.
+  unset($languages[0]);
+}
Index: modules/field/modules/number/number.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/field/modules/number/number.module,v
retrieving revision 1.7
diff -u -r1.7 number.module
--- modules/field/modules/number/number.module	29 Apr 2009 22:36:42 -0000	1.7
+++ modules/field/modules/number/number.module	10 May 2009 22:58:50 -0000
@@ -89,7 +89,7 @@
  * - 'number_min': The value is smaller than the allowed minimum value.
  * - 'number_max': The value is larger than the allowed maximum value.
  */
-function number_field_validate($obj_type, $node, $field, $instance, $items, &$errors) {
+function number_field_validate($obj_type, $node, $field, $instance, $language, $items, &$errors) {
   foreach ($items as $delta => $item) {
     if ($item['value'] != '') {
       if (is_numeric($instance['settings']['min']) && $item['value'] < $instance['settings']['min']) {
Index: modules/field/modules/list/list.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/field/modules/list/list.module,v
retrieving revision 1.4
diff -u -r1.4 list.module
--- modules/field/modules/list/list.module	13 Apr 2009 05:18:18 -0000	1.4
+++ modules/field/modules/list/list.module	10 May 2009 22:58:50 -0000
@@ -98,7 +98,7 @@
  * Possible error codes:
  * - 'list_illegal_value': The value is not part of the list of allowed values.
  */
-function list_field_validate($obj_type, $object, $field, $instance, $items, &$errors) {
+function list_field_validate($obj_type, $object, $field, $instance, $language, $items, &$errors) {
   $allowed_values = list_allowed_values($field);
   foreach ($items as $delta => $item) {
     if (!empty($item['value'])) {