diff --git a/CHANGELOG.md b/CHANGELOG.md
index 04955f5da..0c2143e67 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,8 @@
     * Bug introduced by PR [#482](https://github.com/dpa99c/cordova-plugin-firebasex/pull/482).
 * (Android) Add the Firebase Performance Monitoring Gradle plugin to monitor network traffic.
     * Resolves [#520](https://github.com/dpa99c/cordova-plugin-firebasex/issues/520).
+* (Feature): Add setLanguageCode method for Firebase Auth
+    * Merged from PR [#527](https://github.com/dpa99c/cordova-plugin-firebasex/pull/527).
 
 # Version 11.0.1
 * (iOS) Set the Sign In with Apple capability based on the `IOS_ENABLE_APPLE_SIGNIN` plugin variable.
diff --git a/README.md b/README.md
index f9b475679..e915e41b2 100644
--- a/README.md
+++ b/README.md
@@ -138,6 +138,7 @@ To help ensure this plugin is kept updated, new features are added and bugfixes
     - [verifyPhoneNumber](#verifyphonenumber)
       - [Android](#android-2)
       - [iOS](#ios-2)
+    - [setLanguageCode](#setLanguageCode)
     - [authenticateUserWithEmailAndPassword](#authenticateuserwithemailandpassword)
     - [authenticateUserWithGoogle](#authenticateuserwithgoogle)
       - [Android](#android-3)
@@ -2550,6 +2551,17 @@ You can [set up reCAPTCHA verification for iOS](https://firebase.google.com/docs
 
 This adds the `REVERSED_CLIENT_ID` from the `GoogleService-Info.plist` to the list of custom URL schemes in your Xcode project, so you don't need to do this manually.
 
+### setLanguageCode
+Sets the user-facing language code for auth operations that can be internationalized, such as sendEmailVerification() or verifyPhoneNumber(). This language code should follow the conventions defined by the IETF in BCP47.
+
+**Parameters**:
+- {string} lang - language to change, ex: 'fr' for french
+
+Example usage:
+
+```javascript
+    FirebasePlugin.setLanguageCode('fr'); // will switch to french
+```
 
 ### authenticateUserWithEmailAndPassword
 Authenticates the user with email/password-based user account to obtain a credential that can be used to sign the user in/link to an existing user account/reauthenticate the user.
diff --git a/src/android/FirebasePlugin.java b/src/android/FirebasePlugin.java
index c4bf4a82d..969ca9824 100755
--- a/src/android/FirebasePlugin.java
+++ b/src/android/FirebasePlugin.java
@@ -259,6 +259,8 @@ public boolean execute(String action, JSONArray args, CallbackContext callbackCo
 
             } else if (action.equals("verifyPhoneNumber")) {
                 this.verifyPhoneNumber(callbackContext, args);
+            } else if (action.equals("setLanguageCode")) {
+                this.setLanguageCode(callbackContext, args);
             } else if (action.equals("authenticateUserWithGoogle")) {
                 this.authenticateUserWithGoogle(callbackContext, args);
             } else if (action.equals("authenticateUserWithApple")) {
@@ -1456,6 +1458,27 @@ public void onCodeSent(String verificationId, PhoneAuthProvider.ForceResendingTo
         });
     }
 
+    public void setLanguageCode(final CallbackContext callbackContext, final JSONArray args){
+        cordova.getThreadPool().execute(new Runnable() {
+            public void run() {
+                try {
+                    String lang = args.getString(0);
+
+                    if(lang == null || lang.equals("")){
+                        callbackContext.error("Lang must be specified");
+                        return;
+                    }
+
+                    FirebaseAuth.getInstance().setLanguageCode(lang);
+
+                    Log.d(TAG, "Language code setted to "+lang);
+                } catch (Exception e) {
+                    handleExceptionWithContext(e, callbackContext);
+                }
+            }
+        });
+    }
+    
     public void createUserWithEmailAndPassword(final CallbackContext callbackContext, final JSONArray args){
         cordova.getThreadPool().execute(new Runnable() {
             public void run() {
diff --git a/src/ios/FirebasePlugin.h b/src/ios/FirebasePlugin.h
index 73c26e6cb..5656f0574 100644
--- a/src/ios/FirebasePlugin.h
+++ b/src/ios/FirebasePlugin.h
@@ -10,6 +10,7 @@
 
 // Authentication
 - (void)verifyPhoneNumber:(CDVInvokedUrlCommand*)command;
+- (void)setLanguageCode:(CDVInvokedUrlCommand*)command;
 - (void)createUserWithEmailAndPassword:(CDVInvokedUrlCommand*)command;
 - (void)signInUserWithEmailAndPassword:(CDVInvokedUrlCommand*)command;
 - (void)authenticateUserWithEmailAndPassword:(CDVInvokedUrlCommand*)command;
diff --git a/src/ios/FirebasePlugin.m b/src/ios/FirebasePlugin.m
old mode 100644
new mode 100755
index b957a33f4..5cb510ec0
--- a/src/ios/FirebasePlugin.m
+++ b/src/ios/FirebasePlugin.m
@@ -543,6 +543,16 @@ - (void)verifyPhoneNumber:(CDVInvokedUrlCommand *)command {
     }
 }
 
+- (void)setLanguageCode:(CDVInvokedUrlCommand *)command {
+    NSString* lang = [command.arguments objectAtIndex:0];
+    @try {
+         [FIRAuth auth].languageCode = lang;
+         NSLog(@"Language code setted to %@!", lang);
+    }@catch (NSException *exception) {
+        [self handlePluginExceptionWithContext:exception :command];
+    }
+}
+
 - (void)createUserWithEmailAndPassword:(CDVInvokedUrlCommand*)command {
     @try {
         NSString* email = [command.arguments objectAtIndex:0];
diff --git a/types/index.d.ts b/types/index.d.ts
old mode 100644
new mode 100755
index 187f9226f..2b11ddfae
--- a/types/index.d.ts
+++ b/types/index.d.ts
@@ -138,6 +138,11 @@ interface FirebasePlugin {
         timeOutDuration: number,
         fakeVerificationCode?: string
     ): void
+    setLanguageCode(
+        lang: string,
+        success?: () => void,
+        error?: (err: string) => void
+    ): void
     createUserWithEmailAndPassword(
         email: string,
         password: string,