diff --git a/src/components/Header/LanguageMenu.tsx b/src/components/Header/LanguageMenu.tsx
index 48fcd8f0ef..316daf05ec 100644
--- a/src/components/Header/LanguageMenu.tsx
+++ b/src/components/Header/LanguageMenu.tsx
@@ -30,7 +30,7 @@ const LangMap: Record<keyof Resources, string> = {
 };
 
 const TranslationProgress = ({ lang }: { lang: string }) => {
-  const percent = i18nProgress[lang].percent;
+  const percent = i18nProgress[lang as keyof typeof i18nProgress]?.percent;
   if (typeof percent === 'number' && percent < 100) {
     return (
       <span
diff --git a/vite.config.ts b/vite.config.ts
index 799fdf323d..09887546c7 100644
--- a/vite.config.ts
+++ b/vite.config.ts
@@ -91,7 +91,7 @@ export default defineConfig({
       semicolons: false,
     }),
     i18nProgress({
-      langs: ['en', 'es', 'de', 'zh'],
+      langs: ['en', 'es', 'de', 'zh', 'tr'],
       baseLang: 'en',
       getTranslationDir: (lang) => `./src/locales/${lang}`,
     }),