Where to learn AI

Question

I want to learn about selflearning AI, but I really like the approach taken by Sololearn. Is there a place where I can learn about it in a tutorial sort of way. And which of these programs would you advise as programming language for a cross platform AI. Python (I assume least effect end result), Javascript (with an eye on a web development), Java (I don't know how it reacts in context to different enviroments) or C++ (don't know much about the mobile enviroment in terms of this).