diff --git a/core/lib/Drupal/Core/StringTranslation/TranslatableString.php b/core/lib/Drupal/Core/StringTranslation/TranslatableString.php
index 819b244..37bc5b8 100644
--- a/core/lib/Drupal/Core/StringTranslation/TranslatableString.php
+++ b/core/lib/Drupal/Core/StringTranslation/TranslatableString.php
@@ -40,7 +40,7 @@ class TranslatableString implements SafeStringInterface {
    *
    * @var string
    */
-  protected $TranslatableString;
+  protected $translatableString;
 
   /**
    * The translation arguments.
@@ -91,7 +91,7 @@ public function __construct($string, array $arguments = array(), array $options
    * @return string
    *   The string stored in this wrapper.
    */
-  public function getUnTranslatableString() {
+  public function getUntranslatedString() {
     return $this->string;
   }
 
@@ -135,8 +135,8 @@ public function getArguments() {
    *   The translated string.
    */
   public function render() {
-    if (!isset($this->TranslatableString)) {
-      $this->TranslatableString = $this->getStringTranslation()->translateString($this);
+    if (!isset($this->translatableString)) {
+      $this->translatableString = $this->getStringTranslation()->translateString($this);
     }
 
     // Handle any replacements.
@@ -144,9 +144,9 @@ public function render() {
     //   replacement is not stored so that different sanitization strategies can
     //   be used in different contexts.
     if ($args = $this->getArguments()) {
-      return $this->placeholderFormat($this->TranslatableString, $args);
+      return $this->placeholderFormat($this->translatableString, $args);
     }
-    return $this->TranslatableString;
+    return $this->translatableString;
   }
 
   /**
diff --git a/core/lib/Drupal/Core/StringTranslation/TranslationManager.php b/core/lib/Drupal/Core/StringTranslation/TranslationManager.php
index 649902b..836abd8 100644
--- a/core/lib/Drupal/Core/StringTranslation/TranslationManager.php
+++ b/core/lib/Drupal/Core/StringTranslation/TranslationManager.php
@@ -160,7 +160,7 @@ public function translate($string, array $args = array(), array $options = array
    * {@inheritdoc}
    */
   public function translateString(TranslatableString $translated_string) {
-    return $this->doTranslate($translated_string->getUnTranslatableString(), $translated_string->getOptions());
+    return $this->doTranslate($translated_string->getUntranslatedString(), $translated_string->getOptions());
   }
 
   /**
diff --git a/core/modules/locale/src/LocaleConfigManager.php b/core/modules/locale/src/LocaleConfigManager.php
index 035892f..79628e1 100644
--- a/core/modules/locale/src/LocaleConfigManager.php
+++ b/core/modules/locale/src/LocaleConfigManager.php
@@ -219,10 +219,10 @@ protected function processTranslatableData($name, array $active, array $translat
       }
       else {
         if (locale_is_translatable($langcode)) {
-          $value = $this->translateString($name, $langcode, $item->getUnTranslatableString(), $item->getOption('context'));
+          $value = $this->translateString($name, $langcode, $item->getUntranslatedString(), $item->getOption('context'));
         }
         else {
-          $value = $item->getUnTranslatableString();
+          $value = $item->getUntranslatedString();
         }
         if (!empty($value)) {
           $translated[$key] = $value;
diff --git a/core/modules/locale/src/LocaleConfigSubscriber.php b/core/modules/locale/src/LocaleConfigSubscriber.php
index 36c6d09..1c10480 100644
--- a/core/modules/locale/src/LocaleConfigSubscriber.php
+++ b/core/modules/locale/src/LocaleConfigSubscriber.php
@@ -156,7 +156,7 @@ protected function processTranslatableData($name, array $config, array $translat
         $this->processTranslatableData($name, $config[$key], $item, $langcode, $reference_config);
       }
       else {
-        $this->saveCustomizedTranslation($name, $item->getUnTranslatableString(), $item->getOption('context'), $config[$key], $langcode);
+        $this->saveCustomizedTranslation($name, $item->getUntranslatedString(), $item->getOption('context'), $config[$key], $langcode);
       }
     }
   }
@@ -191,7 +191,7 @@ protected function resetExistingTranslations($name, $translatable, $reference_co
       }
     }
     elseif (!is_array($reference_config)) {
-      $this->saveCustomizedTranslation($name, $translatable->getUnTranslatableString(), $translatable->getOption('context'), $reference_config, $langcode);
+      $this->saveCustomizedTranslation($name, $translatable->getUntranslatedString(), $translatable->getOption('context'), $reference_config, $langcode);
     }
   }
 
diff --git a/core/modules/locale/src/Tests/LocaleExportTest.php b/core/modules/locale/src/Tests/LocaleExportTest.php
index ffa6edc..061c161 100644
--- a/core/modules/locale/src/Tests/LocaleExportTest.php
+++ b/core/modules/locale/src/Tests/LocaleExportTest.php
@@ -111,7 +111,7 @@ public function testExportTranslation() {
     // Ensure no customized translations exist in the file.
     $this->assertNoRaw('msgstr "janvier"', 'French custom translation not present in exported file.');
     // Ensure the untranslated strings exist in the file, and with right quotes.
-    $this->assertRaw($this->getUnTranslatableString(), 'Empty string present in exported file.');
+    $this->assertRaw($this->getUntranslatedString(), 'Empty string present in exported file.');
   }
 
   /**
@@ -171,7 +171,7 @@ public function getCustomPoFile() {
    * @return string
    *   A .po file fragment with an untranslated string.
    */
-  public function getUnTranslatableString() {
+  public function getUntranslatedString() {
     return <<< EOF
 msgid "February"
 msgstr ""
diff --git a/core/tests/Drupal/Tests/UnitTestCase.php b/core/tests/Drupal/Tests/UnitTestCase.php
index d5ff9f6..0b845d3 100644
--- a/core/tests/Drupal/Tests/UnitTestCase.php
+++ b/core/tests/Drupal/Tests/UnitTestCase.php
@@ -227,7 +227,7 @@ public function getStringTranslationStub() {
     $translation->expects($this->any())
       ->method('translateString')
       ->willReturnCallback(function (TranslatableString $wrapper) {
-        return $wrapper->getUnTranslatableString();
+        return $wrapper->getUntranslatedString();
       });
     $translation->expects($this->any())
       ->method('formatPlural')