so people who are born in India but have been living in U.S. use Tropical instead of Vedic.
People from anywhere can use Vedic or Western astrology. It's easier to find Western astrologers if you're in the U.S., though. There aren't nearly as many Vedic ones here.
So, in the Western world, Western astrology is the "official" astrological language. In India (I would assume) Vedic is.
Western tropical astrology is also the primary "language" of this site. We have a section for Vedic, and there are a few posts here and there about Western sidereal astrology, which is a very small subset (uses Western astrological principles but sidereal method to determine the signs), but unless you specify sidereal, it's assumed that you're talking tropical astrology when you post here.