I'm a Microsoft Stack(ASP.NET, C#) developer. Mainly, I develop server side software, windows services, restful apis etc. My client side interaction is really really low. So aside from C# I want to learn a new language. Time is precious and I want to give my focus to a language which have a future. My language list is: Scala (Powerful usage in Twitter) Go (Getting popular and channels are pretty awesome) Erlang (Stable server side programs. Used at Whatsapp) You can give advice for the above or you can give me a better option. My only exception is Objective-C. I don't want to get in that one. Thanks