diff --git a/lib/modules/auth/index.js b/lib/modules/auth/index.js
index accc5f8e..bf32aa26 100644
--- a/lib/modules/auth/index.js
+++ b/lib/modules/auth/index.js
@@ -327,7 +327,7 @@ export default class Auth extends ModuleBase {
    * @returns {*}
    */
   useDeviceLanguage() {
-    return this._native.useDeviceLanguage();
+    this._native.useDeviceLanguage();
   }
 
   /**
@@ -335,8 +335,8 @@ export default class Auth extends ModuleBase {
    * @param code
    * @returns {*}
    */
-  set languageCode(code) {
-    return this._native.setLanguageCode(code);
+  set languageCode(code: string) {
+    this._native.setLanguageCode(code);
   }
 
   /**