Well uh. . . I was an undergrad there a few years back. I took a fair number of grad-level classes. What's your question?
You should know that Columbia as a university doesn't have a formal linguistics program. It's (or so I'm told) one of the top programs in the world for East Asian area studies, but if you're looking for linguistics as a social science, this might not be your best choice. What are you planning? Feel free to PM.