What is the function of 是 in this sentence: 你是怎么学习英语的？ Am I right to assume that the question is about the other person's personal method of studying English? And would omitting the 是 make the question more general?

(Is this an example for the topic-comment structure: 
http://resources.allsetlearning.com/chinese/grammar/Topic-comment_sentences)
是的 constructs are for emphasizing.

你是怎么学习英语的？ = How did you learn English?

你是什么时候来的？ = When did you come here?

我是来看病的 = I have come to get a medical exam (as opposed to a social visit).