diff --git a/core/configuration/library.py b/core/configuration/library.py
index 8d60b839b9..f5330e27de 100644
--- a/core/configuration/library.py
+++ b/core/configuration/library.py
@@ -643,7 +643,7 @@ def validate_language_codes(
                     field_label = cls.get_form_field_label(field.name)
                     raise SettingsValidationError(
                         problem_detail=UNKNOWN_LANGUAGE.detailed(
-                            f"{field_label}: {language} is not a valid language code."
+                            f'"{field_label}": "{language}" is not a valid language code.'
                         )
                     )
         return value
diff --git a/tests/api/admin/controller/test_library.py b/tests/api/admin/controller/test_library.py
index e8834dd784..95f8ce824e 100644
--- a/tests/api/admin/controller/test_library.py
+++ b/tests/api/admin/controller/test_library.py
@@ -340,7 +340,7 @@ def test_libraries_post_errors(self, settings_ctrl_fixture):
                 settings_ctrl_fixture.manager.admin_library_settings_controller.process_post()
             assert excinfo.value.problem_detail.uri == UNKNOWN_LANGUAGE.uri
             assert (
-                "zzz is not a valid language code"
+                '"zzz" is not a valid language code'
                 in excinfo.value.problem_detail.detail
             )