diff --git a/src/shared/config.ts b/src/shared/config.ts
index 281ce539..b5f152ab 100644
--- a/src/shared/config.ts
+++ b/src/shared/config.ts
@@ -47,6 +47,7 @@ export function resolveSiteDataByRoute(siteData: SiteData, route: string) {
       // clean the locales to reduce the bundle size
       locales: {}
     },
+    lang: localeThemeConfig.lang || siteData.lang,
     locales: {}
   }
 }