diff --git a/apps/frontend/src/auth/AuthService.ts b/apps/frontend/src/auth/AuthService.ts
index 6629a18..0ad08df 100644
--- a/apps/frontend/src/auth/AuthService.ts
+++ b/apps/frontend/src/auth/AuthService.ts
@@ -1,3 +1,4 @@
+import i18n from "i18next";
 import { User, UserManager, WebStorageStateStore } from "oidc-client-ts";
 
 const CALLBACK_PATH = "/auth/callback";
@@ -68,11 +69,11 @@ export class AuthService {
 
     // prompt=login shows the login form even though the guest already has a session.
     public login(returnTo = currentPath()): Promise<void> {
-        return this.userManager.signinRedirect({ prompt: "login", state: { returnTo } });
+        return this.userManager.signinRedirect({ prompt: "login", ui_locales: i18n.language, state: { returnTo } });
     }
 
     public signUp(returnTo = currentPath()): Promise<void> {
-        return this.userManager.signinRedirect({ prompt: "create", state: { returnTo } });
+        return this.userManager.signinRedirect({ prompt: "create", ui_locales: i18n.language, state: { returnTo } });
     }
 
     public logout(): Promise<void> {