If I'm learning a human language I can do it in many different ways. But the key distinction would be, if for example I'm using only books to study by myself, or using only some recorded course on the internet - it would be called self-study. But if for example I will go to a class teaching that language, or to a private teacher, or to summer camp, or join online platform pairing students teachers etc. then neither of those will count as self-study.