frontend/src/App.tsx

@@ -1,5 +1,7 @@
+import { useEffect } from "react";
 import "./App.css";
 import suLogoLandscape from "./assets/SU_logo_optimized.svg";
+import { setLanguagePreference } from "./hooks/backend.ts";
 import { ProfileContext } from "./hooks/profile.ts";
 import Studentportalen from "./Studentportalen.tsx";
 import { useViewTransitioningFetch } from "./hooks/fetch";
@@ -7,6 +9,10 @@ import { useViewTransitioningFetch } from "./hooks/fetch";
 function App() {
   const { data: profile, error } = useViewTransitioningFetch("/profile");
 
+  useEffect(() => {
+    setLanguagePreference(profile?.language);
+  }, [profile?.language]);
+
   if (!profile) {
     return splashScreen("Loading...");
   }

frontend/src/hooks/backend.ts

@@ -1,6 +1,12 @@
 import createClient, { Middleware } from "openapi-fetch";
 import type { paths } from "../lib/api";
 
+let languagePreference: string | undefined;
+
+export function setLanguagePreference(language: string | undefined) {
+  languagePreference = language;
+}
+
 const client = createClient<paths>({
   baseUrl: import.meta.env.VITE_BACKEND_URL,
 });
@@ -31,7 +37,8 @@ const includeCsrfToken: Middleware = {
 
 const includeAcceptLanguage: Middleware = {
   onRequest({ request }) {
-    const language = navigator.language.split("-")[0] || "en";
+    const language =
+      languagePreference ?? navigator.language.split("-")[0] ?? "en";
     request.headers.set("Accept-Language", language);
     return request;
   },