diff --git a/nixos/modules/services/games/ghost-one.nix b/nixos/modules/services/games/ghost-one.nix
index 5762148df2bb..71ff6bb2f3f0 100644
--- a/nixos/modules/services/games/ghost-one.nix
+++ b/nixos/modules/services/games/ghost-one.nix
@@ -21,8 +21,7 @@ in
 
       language = mkOption {
         default = "English";
-        type = types.addCheck types.str
-          (lang: elem lang [ "English" "Spanish" "Russian" "Serbian" "Turkish" ]);
+        type = types.enum [ "English" "Spanish" "Russian" "Serbian" "Turkish" ];
         description = "The language of bot messages: English, Spanish, Russian, Serbian or Turkish.";
       };