diff --git c/core/lib/Drupal/Core/Entity/ContentEntityBase.php w/core/lib/Drupal/Core/Entity/ContentEntityBase.php
index 33a7b77..8d889a3 100644
--- c/core/lib/Drupal/Core/Entity/ContentEntityBase.php
+++ w/core/lib/Drupal/Core/Entity/ContentEntityBase.php
@@ -260,16 +260,6 @@ public function isDefaultTranslation() {
   /**
    * {@inheritdoc}
    */
-  public function isTranslation() {
-    if ($this->language()->getId() != $this->getUntranslated()->language()->getId()) {
-      return TRUE;
-    }
-    return FALSE;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
   public function getRevisionId() {
     return $this->getEntityKey('revision');
   }
diff --git c/core/lib/Drupal/Core/Entity/ContentEntityDeleteForm.php w/core/lib/Drupal/Core/Entity/ContentEntityDeleteForm.php
index 8a1d577..6116520 100644
--- c/core/lib/Drupal/Core/Entity/ContentEntityDeleteForm.php
+++ w/core/lib/Drupal/Core/Entity/ContentEntityDeleteForm.php
@@ -28,7 +28,7 @@ public function submitForm(array &$form, FormStateInterface $form_state) {
     $entity = $this->getEntity();
 
     // Make sure that deleting a translation does not delete the whole entity.
-    if ($entity->isTranslation()) {
+    if (!$entity->isDefaultTranslation()) {
       $untranslated_entity = $entity->getUntranslated();
       $untranslated_entity->removeTranslation($entity->language()->getId());
       $untranslated_entity->save();
@@ -50,7 +50,7 @@ protected function getDeletionMessage() {
     /** @var \Drupal\Core\Entity\ContentEntityInterface $entity */
     $entity = $this->getEntity();
 
-    if ($entity->isTranslation()) {
+    if (!$entity->isDefaultTranslation()) {
       return $this->t('The @entity-type %label @language translation has been deleted.', [
         '@entity-type' => $entity->getEntityType()->getLowercaseLabel(),
         '%label'       => $entity->label(),
@@ -68,7 +68,7 @@ protected function logDeletionMessage() {
     /** @var \Drupal\Core\Entity\ContentEntityInterface $entity */
     $entity = $this->getEntity();
 
-    if ($entity->isTranslation()) {
+    if (!$entity->isDefaultTranslation()) {
       $this->logger($entity->getEntityType()->getProvider())->notice('The @entity-type %label @language translation has been deleted.', [
         '@entity-type' => $entity->getEntityType()->getLowercaseLabel(),
         '%label'       => $entity->label(),
@@ -87,7 +87,7 @@ public function getQuestion() {
     /** @var \Drupal\Core\Entity\ContentEntityInterface $entity */
     $entity = $this->getEntity();
 
-    if ($entity->isTranslation()) {
+    if (!$entity->isDefaultTranslation()) {
       return $this->t('Are you sure you want to delete @language translation of the @entity-type %label?', array(
         '@language' => $entity->language()->getName(),
         '@entity-type' => $this->getEntity()->getEntityType()->getLowercaseLabel(),
diff --git c/core/lib/Drupal/Core/TypedData/TranslatableInterface.php w/core/lib/Drupal/Core/TypedData/TranslatableInterface.php
index 77059a0..73b288d 100644
--- c/core/lib/Drupal/Core/TypedData/TranslatableInterface.php
+++ w/core/lib/Drupal/Core/TypedData/TranslatableInterface.php
@@ -29,14 +29,6 @@ public function language();
   public function isDefaultTranslation();
 
   /**
-   * Checks whether the data is a translation.
-   *
-   * @return bool
-   *   TRUE if the data a translation., FALSE otherwise.
-   */
-  public function isTranslation();
-
-  /**
    * Returns the languages the data is translated to.
    *
    * @param bool $include_default
diff --git c/core/modules/content_translation/src/ContentTranslationHandler.php w/core/modules/content_translation/src/ContentTranslationHandler.php
index 45efcd9..3f82a78 100644
--- c/core/modules/content_translation/src/ContentTranslationHandler.php
+++ w/core/modules/content_translation/src/ContentTranslationHandler.php
@@ -608,7 +608,7 @@ function entityFormDelete($form, FormStateInterface $form_state) {
    * {@inheritdoc}
    */
   public function entityDeleteFormAlter(array &$form, FormStateInterface $form_state, ContentEntityInterface $entity) {
-    if (!$entity->isTranslation()) {
+    if ($entity->isDefaultTranslation()) {
       $languages = [];
       foreach ($entity->getTranslationLanguages() as $language) {
         $languages[] = $language->getName();
diff --git c/core/modules/node/src/Form/NodeDeleteForm.php w/core/modules/node/src/Form/NodeDeleteForm.php
index 17a58bb..cd36d98 100644
--- c/core/modules/node/src/Form/NodeDeleteForm.php
+++ w/core/modules/node/src/Form/NodeDeleteForm.php
@@ -25,7 +25,7 @@ protected function getDeletionMessage() {
     $node_type_storage = $this->entityManager->getStorage('node_type');
     $node_type = $node_type_storage->load($entity->bundle())->label();
 
-    if ($entity->isTranslation()) {
+    if (!$entity->isDefaultTranslation()) {
       return $this->t('@language translation of the @type %label has been deleted.', [
         '@language' => $entity->language()->getName(),
         '@type' => $node_type,
@@ -44,7 +44,9 @@ protected function getDeletionMessage() {
    */
   public function submitForm(array &$form, FormStateInterface $form_state) {
     parent::submitForm($form, $form_state);
-    $form_state->setRedirect('<front>');
+    if ($this->getEntity()->isDefaultTranslation()) {
+      $form_state->setRedirect('<front>');
+    }
   }
 
   /**