diff --git a/src/infrastructure/internationalization/translation/PhabricatorUSEnglishTranslation.php b/src/infrastructure/internationalization/translation/PhabricatorUSEnglishTranslation.php
--- a/src/infrastructure/internationalization/translation/PhabricatorUSEnglishTranslation.php
+++ b/src/infrastructure/internationalization/translation/PhabricatorUSEnglishTranslation.php
@@ -386,6 +386,13 @@
         ),
       ),
 
+      '%s added %s reviewer(s) for %s: %s.' => array(
+        array(
+          '%s added a reviewer for %3$s: %4$s.',
+          '%s added reviewers for %3$s: %4$s.',
+        ),
+      ),
+
       '%s removed %s reviewer(s): %s.' => array(
         array(
           '%s removed a reviewer: %3$s.',
@@ -393,6 +400,13 @@
         ),
       ),
 
+      '%s removed %s reviewer(s) for %s: %s.' => array(
+        array(
+          '%s removed a reviewer for %3$s: %4$s.',
+          '%s removed reviewers for %3$s: %4$s.',
+        ),
+      ),
+
       '%d other(s)' => array(
         '1 other',
         '%d others',