AI types tend to write their own special purpose languages. In one class we used a different language every week. Or close to that.
You can start by learning LISP. It and PROLOG are the two major languages used by AI. I would look into CLISP in that it is open source and has a sizeable following.
I would start by finding an online LISP tutorial. There are several out there.
Once you have worked through a few tutorials and have a good feel for the language you can start to study AI itself.