public Task SpeechAsync(string text, string language = null) { CrossLocale?locale = null; if (language != null) { locale = synthesizer.GetInstalledLanguages().FirstOrDefault(l => l.Language.StartsWith(language)); locale = locale.Value.Language != null ? locale : null; } synthesizer.Speak(text, crossLocale: locale); return(Task.FromResult <object>(null)); }