I had another friend from NYC and there were a lot of guys in my unit from there as well. I got to where I could tell what part of the city you came from, and still can, mostly, even though I wear a hearing aid in my right ear and am deaf in my left ear.
I recently tried it again at a local store my wife and I shop at.
We were talking to the check-out clerk lady and I said, “What part of the Bronx are you from?” Her eyes got real big and said, “How did you know?” Then I told her about my friends in the Marines........
Indeed. New York Accents are very similar to Boston Accents, in that one can pinpoint the Burrough or Neighborhood from which it originates.