diff --git a/core/modules/aggregator/src/Entity/Feed.php b/core/modules/aggregator/src/Entity/Feed.php
index a442005..fc1b9ee 100644
--- a/core/modules/aggregator/src/Entity/Feed.php
+++ b/core/modules/aggregator/src/Entity/Feed.php
@@ -151,7 +151,7 @@ public static function baseFieldDefinitions(EntityTypeInterface $entity_type) {
         'weight' => -5,
       ))
       ->setDisplayConfigurable('form', TRUE)
-      ->addConstraint('UniqueField', ['message' => 'A feed named %value already exists. Enter a unique title.']);
+      ->addConstraint('UniqueField', ['message' => t('A feed named %value already exists. Enter a unique title.')]);
 
     $fields['langcode'] = BaseFieldDefinition::create('language')
       ->setLabel(t('Language code'))
@@ -173,7 +173,7 @@ public static function baseFieldDefinitions(EntityTypeInterface $entity_type) {
         'weight' => -3,
       ))
       ->setDisplayConfigurable('form', TRUE)
-      ->addConstraint('UniqueField', ['message' => 'A feed with this URL %value already exists. Enter a unique URL.']);
+      ->addConstraint('UniqueField', ['message' => t('A feed with this URL %value already exists. Enter a unique URL.')]);
 
     $intervals = array(900, 1800, 3600, 7200, 10800, 21600, 32400, 43200, 64800, 86400, 172800, 259200, 604800, 1209600, 2419200);
     $period = array_map(array(\Drupal::service('date.formatter'), 'formatInterval'), array_combine($intervals, $intervals));