diff --git a/docs/.vitepress/lang.js b/docs/.vitepress/lang.js
index 11c385cefd..e4cfefddd4 100644
--- a/docs/.vitepress/lang.js
+++ b/docs/.vitepress/lang.js
@@ -2,18 +2,15 @@
   const supportedLangs = window.supportedLangs
   const cacheKey = 'preferred_lang'
   const defaultLang = 'en-US'
-  // docs supported languages
-  const langAlias = {
-    en: 'en-US',
-    fr: 'fr-FR',
-    es: 'es-ES',
+  const handleNavigatorLang = (navLang) => {
+    const { language, region } = new Intl.Locale(navLang).maximize()
+    return `${language}-${region}`
   }
-  let userPreferredLang = localStorage.getItem(cacheKey) || navigator.language
-  const language =
-    langAlias[userPreferredLang] ||
-    (supportedLangs.includes(userPreferredLang)
-      ? userPreferredLang
-      : defaultLang)
+  let userPreferredLang =
+    localStorage.getItem(cacheKey) || handleNavigatorLang(navigator.language)
+  const language = supportedLangs.includes(userPreferredLang)
+    ? userPreferredLang
+    : defaultLang
   localStorage.setItem(cacheKey, language)
   userPreferredLang = language
   if (!location.pathname.startsWith(`/${userPreferredLang}`)) {