Recently we started working with Apple Swift language. It’s pretty simple but very power full language. Learning curve is hard – because it’s pretty new language, but from the other hand it’s good – because there is a lot of freshmen questions on StackOverflow and plenty of articles .
Because most of the stuff is related with REST communication with APIs core of my software works with JSON objects. In general we are looking also something for HTTP communication, uploading files and so on.