@@ -211,16 +211,18 @@ public async Task<FirebaseAuthLink> ChangeUserEmail(string idToken, string newEm
 
 return await this.ExecuteWithPostContentAsync(GoogleUpdateUserPassword, content).ConfigureAwait(false);
 }
-
+
 /// <summary>
 /// Creates new user with given credentials.
 /// </summary>
 /// <param name="email"> The email. </param>
 /// <param name="password"> The password. </param>
 /// <param name="displayName"> Optional display name. </param>
 /// <param name="sendVerificationEmail"> Optional. Whether to send user a link to verfiy his email address. </param>
+/// <param name="locale"> The language code of language that the email will be in. </param>
 /// <returns> The <see cref="FirebaseAuth"/>. </returns>
-public async Task<FirebaseAuthLink> CreateUserWithEmailAndPasswordAsync(string email, string password, string displayName = "", bool sendVerificationEmail = false)
+public async Task<FirebaseAuthLink> CreateUserWithEmailAndPasswordAsync(string email, string password, string displayName = "",
+bool sendVerificationEmail = false, string locale = null)
 {
 var content = $"{{\"email\":\"{email}\",\"password\":\"{password}\",\"returnSecureToken\":true}}";
 
@@ -239,7 +241,7 @@ public async Task<FirebaseAuthLink> CreateUserWithEmailAndPasswordAsync(string e
 if (sendVerificationEmail)
 {
 //send verification email
-await this.SendEmailVerificationAsync(signup).ConfigureAwait(false);
+await this.SendEmailVerificationAsync(signup, locale).ConfigureAwait(false);
 }
 
 return signup;
@@ -315,14 +317,21 @@ public async Task DeleteUserAsync(string firebaseToken)
 /// Sends user an email with a link to reset his password.
 /// </summary>
 /// <param name="email"> The email. </param>
-public async Task SendPasswordResetEmailAsync(string email)
+/// <param name="locale"> The language code of language that the email will be in. </param>
+public async Task SendPasswordResetEmailAsync(string email, string locale = null)
 {
 var content = $"{{\"requestType\":\"PASSWORD_RESET\",\"email\":\"{email}\"}}";
 var responseData = "N/A";
 
 try
 {
-var response = await this.client.PostAsync(new Uri(string.Format(GoogleGetConfirmationCodeUrl, this.authConfig.ApiKey)), new StringContent(content, Encoding.UTF8, "application/json")).ConfigureAwait(false);
+var httpContent = new StringContent(content, Encoding.UTF8, "application/json");
+if (locale != null)
+{
+httpContent = AddFirebaseLocaleHeader(httpContent, locale);
+}
+
+var response = await this.client.PostAsync(new Uri(string.Format(GoogleGetConfirmationCodeUrl, this.authConfig.ApiKey)), httpContent).ConfigureAwait(false);
 responseData = await response.Content.ReadAsStringAsync().ConfigureAwait(false);
 
 response.EnsureSuccessStatusCode();
@@ -338,11 +347,18 @@ public async Task SendPasswordResetEmailAsync(string email)
 /// Sends user an email with a link to verify his email address.
 /// </summary>
 /// <param name="firebaseToken"> The FirebaseToken (idToken) of an authenticated user. </param>
-public async Task SendEmailVerificationAsync(string firebaseToken)
+/// <param name="locale"> The language code of language that the email will be in. </param>
+public async Task SendEmailVerificationAsync(string firebaseToken, string locale = null)
 {
 var content = $"{{\"requestType\":\"VERIFY_EMAIL\",\"idToken\":\"{firebaseToken}\"}}";
 
-var response = await this.client.PostAsync(new Uri(string.Format(GoogleGetConfirmationCodeUrl, this.authConfig.ApiKey)), new StringContent(content, Encoding.UTF8, "application/json")).ConfigureAwait(false);
+var httpContent = new StringContent(content, Encoding.UTF8, "application/json");
+if (locale != null)
+{
+httpContent = AddFirebaseLocaleHeader(httpContent, locale);
+}
+
+var response = await this.client.PostAsync(new Uri(string.Format(GoogleGetConfirmationCodeUrl, this.authConfig.ApiKey)), httpContent).ConfigureAwait(false);
 
 response.EnsureSuccessStatusCode();
 }
@@ -351,9 +367,10 @@ public async Task SendEmailVerificationAsync(string firebaseToken)
 /// Sends user an email with a link to verify his email address.
 /// </summary>
 /// <param name="auth"> The authenticated user to verify email address. </param>
-public async Task SendEmailVerificationAsync(FirebaseAuth auth)
+/// <param name="locale"> The language code of language that the email will be in. </param>
+public async Task SendEmailVerificationAsync(FirebaseAuth auth, string locale = null)
 {
-await this.SendEmailVerificationAsync(auth.FirebaseToken).ConfigureAwait(false);
+await this.SendEmailVerificationAsync(auth.FirebaseToken, locale).ConfigureAwait(false);
 }
 
 /// <summary>
@@ -506,6 +523,21 @@ public void Dispose()
 this.client.Dispose();
 }
 
+/// <summary>
+/// Adds firebase locale header used to send email in chosen language.
+/// If locale is incorrect default language will be chosen.
+/// </summary>
+/// <typeparam name="T"> Class deriving from HttpContent </typeparam>
+/// <param name="content"> Http content to add locale header to. </param>
+/// <param name="locale"> Locale string. </param>
+/// <returns> Passed http content with added header. </returns>
+private static T AddFirebaseLocaleHeader<T>(T content, string locale) where T : HttpContent
+{
+content.Headers.Add("X-Firebase-Locale", locale);
+
+return content;
+}
+
 private async Task<FirebaseAuthLink> ExecuteWithPostContentAsync(string googleUrl, string postContent)
 {
 string responseData = "N/A";

@@ -14,15 +14,18 @@ public interface IFirebaseAuthProvider
 /// <param name="password"> The password. </param>
 /// <param name="displayName"> Optional display name. </param>
 /// <param name="sendVerificationEmail"> Optional. Whether to send user a link to verfiy his email address. </param>
+/// <param name="locale"> The language code of language that the email will be in. </param>
 /// <returns> The <see cref="FirebaseAuthLink"/>. </returns>
-Task<FirebaseAuthLink> CreateUserWithEmailAndPasswordAsync(string email, string password, string displayName = "", bool sendVerificationEmail = false);
-
+Task<FirebaseAuthLink> CreateUserWithEmailAndPasswordAsync(string email, string password, string displayName = "",
+bool sendVerificationEmail = false, string locale = null);
+
 /// <summary>
 /// Sends user an email with a link to reset his password.
 /// </summary>
 /// <param name="email"> The email. </param>
+/// <param name="locale"> The language code of language that the email will be in. </param>
 /// <returns> The <see cref="Task"/>. </returns>
-Task SendPasswordResetEmailAsync(string email);
+Task SendPasswordResetEmailAsync(string email, string locale = null);
 
 /// <summary>
 /// Sign in user anonymously. He would still have a user id and access token generated, but name and other personal user properties will be null.
@@ -147,13 +150,15 @@ public interface IFirebaseAuthProvider
 /// Sends user an email with a link to verify his email address.
 /// </summary>
 /// <param name="firebaseToken"> The FirebaseToken (idToken) of an authenticated user. </param>
-Task SendEmailVerificationAsync(string firebaseToken);
+/// <param name="locale"> The language code of language that the email will be in. </param>
+Task SendEmailVerificationAsync(string firebaseToken, string locale = null);
 
 /// <summary>
 /// Sends user an email with a link to verify his email address.
 /// </summary>
 /// <param name="auth"> The authenticated user to verify email address. </param>
-Task SendEmailVerificationAsync(FirebaseAuth auth);
+/// <param name="locale"> The language code of language that the email will be in. </param>
+Task SendEmailVerificationAsync(FirebaseAuth auth, string locale = null);
 
 /// <summary>
 /// Refreshes given auth using its refresh token.