diff --git a/core/lib/Drupal/Component/Gettext/PoItem.php b/core/lib/Drupal/Component/Gettext/PoItem.php
index 94eb1b8fe3..7fae18b459 100644
--- a/core/lib/Drupal/Component/Gettext/PoItem.php
+++ b/core/lib/Drupal/Component/Gettext/PoItem.php
@@ -159,7 +159,7 @@ public function setPlural($plural) {
   /**
    * {@inheritdoc}
    */
-  public function setPluralCount($pluralCount) {
+  public function setPluralCount(int $pluralCount) {
     $this->pluralCount = $pluralCount;
     return $this;
   }
@@ -176,7 +176,7 @@ public function isPlural() {
   /**
    * {@inheritdoc}
    */
-  public function getPluralCount() {
+  public function getPluralCount(): int {
     return $this->pluralCount;
   }
 
diff --git a/core/lib/Drupal/Component/Gettext/PoPluralCountAwareInterface.php b/core/lib/Drupal/Component/Gettext/PoPluralCountAwareInterface.php
index ca0a45fe18..f3cc92fccb 100644
--- a/core/lib/Drupal/Component/Gettext/PoPluralCountAwareInterface.php
+++ b/core/lib/Drupal/Component/Gettext/PoPluralCountAwareInterface.php
@@ -3,7 +3,7 @@
 namespace Drupal\Component\Gettext;
 
 /**
- * Shared interface definition for all Gettext PO elements that need to know about plurals.
+ * Interface for all Gettext PO elements that need to know about plurals.
  */
 interface PoPluralCountAwareInterface {
 
@@ -13,7 +13,7 @@ interface PoPluralCountAwareInterface {
    * @return int
    *   The plural count.
    */
-  public function getPluralCount();
+  public function getPluralCount(): int;
 
   /**
    * Sets the plural count.
@@ -23,6 +23,6 @@ public function getPluralCount();
    *
    * @return self
    */
-  public function setPluralCount($pluralCount);
+  public function setPluralCount(int $pluralCount);
 
 }
diff --git a/core/lib/Drupal/Component/Gettext/PoStreamReader.php b/core/lib/Drupal/Component/Gettext/PoStreamReader.php
index 513df9045e..8f4579d159 100644
--- a/core/lib/Drupal/Component/Gettext/PoStreamReader.php
+++ b/core/lib/Drupal/Component/Gettext/PoStreamReader.php
@@ -136,14 +136,14 @@ public function setHeader(PoHeader $header) {
   /**
    * {@inheritdoc}
    */
-  public function getPluralCount() {
+  public function getPluralCount(): int {
     return $this->pluralCount;
   }
 
   /**
    * {@inheritdoc}
    */
-  public function setPluralCount($pluralCount) {
+  public function setPluralCount(int $pluralCount) {
     $this->pluralCount = $pluralCount;
     return $this;
   }
diff --git a/core/lib/Drupal/Component/Gettext/PoStreamWriter.php b/core/lib/Drupal/Component/Gettext/PoStreamWriter.php
index 3da14cd911..1bb2abbe02 100644
--- a/core/lib/Drupal/Component/Gettext/PoStreamWriter.php
+++ b/core/lib/Drupal/Component/Gettext/PoStreamWriter.php
@@ -85,14 +85,14 @@ public function setLangcode($langcode) {
   /**
    * {@inheritdoc}
    */
-  public function getPluralCount() {
+  public function getPluralCount(): int {
     return $this->pluralCount;
   }
 
   /**
    * {@inheritdoc}
    */
-  public function setPluralCount($pluralCount) {
+  public function setPluralCount(int $pluralCount) {
     $this->pluralCount = $pluralCount;
     return $this;
   }