diff --git a/app/src/main/res/values-de/strings.xml b/app/src/main/res/values-de/strings.xml
index e7d9b3a..a250299 100644
--- a/app/src/main/res/values-de/strings.xml
+++ b/app/src/main/res/values-de/strings.xml
@@ -89,5 +89,6 @@
     <string name="difficulty_description">Drücke oder wische über die Sterne um den Schwierigkeitsgrad zu ändern.</string>
     <string name="view_help">Siehe Hilfe</string>
     <string name="okay">Okay</string>
+    <string name="difficulty_challenge">Profi</string>
 
 </resources>
\ No newline at end of file
diff --git a/app/src/main/res/values-es/strings.xml b/app/src/main/res/values-es/strings.xml
index d6f90cf..6fcfd54 100644
--- a/app/src/main/res/values-es/strings.xml
+++ b/app/src/main/res/values-es/strings.xml
@@ -9,6 +9,7 @@
     <string name="difficulty_easy">Fácil</string>
     <string name="difficulty_hard">Difícil</string>
     <string name="difficulty_moderate">Normal</string>
+    <string name="difficulty_challenge">Reto</string>
     <string name="gametype_unspecified">No especificado </string>
     <string name="generating">Generando nuevo nivel en segundo plano…</string>
     <string name="help_delete">Borrar</string>
diff --git a/app/src/main/res/values-fr/strings.xml b/app/src/main/res/values-fr/strings.xml
index 9b0d9dd..94ee99f 100644
--- a/app/src/main/res/values-fr/strings.xml
+++ b/app/src/main/res/values-fr/strings.xml
@@ -8,6 +8,7 @@
     <string name="difficulty_easy">Facile</string>
     <string name="difficulty_hard">Difficile</string>
     <string name="difficulty_moderate">Normal</string>
+    <string name="difficulty_challenge">Challenge</string>
     <string name="gametype_unspecified">Indéterminé</string>
     <string name="generating">Générer nouveau niveau en arrière-plan…</string>
     <string name="header_help">Aide</string>
diff --git a/app/src/main/res/values-ja/strings.xml b/app/src/main/res/values-ja/strings.xml
index 9598158..45dc560 100644
--- a/app/src/main/res/values-ja/strings.xml
+++ b/app/src/main/res/values-ja/strings.xml
@@ -62,6 +62,7 @@
     <string name="difficulty_easy">簡単</string>
     <string name="difficulty_moderate">標準</string>
     <string name="difficulty_hard">難しい</string>
+    <string name="difficulty_challenge">チャレンジ</string>
 
     <!--###GameActivity -->
     <string name="gametype_unspecified">未指定</string>
diff --git a/app/src/main/res/values-ru/strings.xml b/app/src/main/res/values-ru/strings.xml
index 00b00c8..4f710bb 100644
--- a/app/src/main/res/values-ru/strings.xml
+++ b/app/src/main/res/values-ru/strings.xml
@@ -8,6 +8,7 @@
     <string name="difficulty_easy">Легкий</string>
     <string name="difficulty_hard">Сложный</string>
     <string name="difficulty_moderate">Средний</string>
+    <string name="difficulty_challenge">вызов</string>
     <string name="gametype_unspecified">Необычный</string>
     <string name="generating">Генерирую новый уровень на заднем плане…</string>
     <string name="header_help">Помощь</string>
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index eb262de..e8debba 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -140,7 +140,7 @@
     <string name="help_permissions_summary">Privacy Friendly Sudoku does not use any permissions.</string>
     <string name="okay">Okay</string>
     <string name="view_help">View Help</string>
-    <string name="difficulty_challenge" translatable="false">Challenge</string>
+    <string name="difficulty_challenge">Challenge</string>
     <string name="pref_highlightInputError" translatable="false">Highlight input mistakes</string>
     <string name="pref_keep_screen_on">Keep Screen On</string>
     <string name="pref_keep_screen_on_summary">Don\'t turn the screen off while playing</string>