fix: (Duplicate) prevent multi-language survey buttons from falling back to English (#7559)

apps/web/modules/analysis/components/ShareSurveyLink/components/LanguageDropdown.tsx

@@ -1,6 +1,6 @@
 import { Languages } from "lucide-react";
-import { getLanguageLabel } from "@formbricks/i18n-utils/src/utils";
 import { useTranslation } from "react-i18next";
+import { getLanguageLabel } from "@formbricks/i18n-utils/src/utils";
 import { TSurvey } from "@formbricks/types/surveys/types";
 import { TUserLocale } from "@formbricks/types/user";
 import { getEnabledLanguages } from "@/lib/i18n/utils";
@@ -18,11 +18,7 @@ interface LanguageDropdownProps {
   locale: TUserLocale;
 }
 
-export const LanguageDropdown = ({
-  survey,
-  setLanguage,
-  locale,
-}: LanguageDropdownProps) => {
+export const LanguageDropdown = ({ survey, setLanguage, locale }: LanguageDropdownProps) => {
   const { t } = useTranslation();
   const enabledLanguages = getEnabledLanguages(survey.languages ?? []);
 
@@ -33,7 +29,10 @@ export const LanguageDropdown = ({
   return (
     <DropdownMenu>
       <DropdownMenuTrigger asChild>
-        <Button variant="secondary" title={t("common.select_language")} aria-label={t("common.select_language")}>
+        <Button
+          variant="secondary"
+          title={t("common.select_language")}
+          aria-label={t("common.select_language")}>
           <Languages className="h-5 w-5" />
         </Button>
       </DropdownMenuTrigger>

packages/surveys/src/lib/i18n.ts

@@ -41,9 +41,16 @@ export const getLocalizedValue = (
  * This ensures translations are always available, even when called from API routes
  */
 export const getTranslations = (languageCode: string): TFunction => {
+  // "default" is a Formbricks-internal language identifier, not a valid i18next locale.
+  // When "default" is passed, use the current i18n language (which was already resolved
+  // to a real locale by the I18nProvider or LanguageSwitch). Calling
+  // i18n.changeLanguage("default") would cause i18next to fall back to "en", resetting
+  // the user's selected language (see issue #7515).
+  const resolvedCode = languageCode === "default" ? i18n.language : languageCode;
+
   // Ensure the language is set (i18n.changeLanguage is synchronous when resources are already loaded)
-  if (i18n.language !== languageCode) {
-    i18n.changeLanguage(languageCode);
+  if (i18n.language !== resolvedCode) {
+    i18n.changeLanguage(resolvedCode);
   }
-  return i18n.getFixedT(languageCode);
+  return i18n.getFixedT(resolvedCode);
 };