I’m an English major, too—so I guess I’m in a similar situation, although I don’t necessarily have the “real-world” experience others here probably have. The department at the school I go to (not in NY) has a TESL certificate program they offer, and many of the classes are linguistics based. They also include an “intercultural communications” course and then English classes specific to teaching a second language learner. I say that just to give an example of one TESL program’s content. If your major also offers a TESL certificate, I would do that. (I’m assuming it doesn’t, though, hence the question?)—in that case: If I were you, I would probably do the linguistics concentration, because I think that depth of understanding the language’s mechanics will be useful, and then I would see if I could pick up any courses in teaching English as a second language (maybe in the English department, maybe in the Education department, etc.). Best of luck! I wish I had done more in linguistics and TESL