In NYC we have more Peurto Ricans living here than in Peurto Rico, and now the Dominican population is growning very fast here. In the past I dated a ton of spanish women and never learned any spanish. It can't hurt to learn...especially 80% of my building speaks spanish. I am making an effort to learn Japanese since my wifes parents speak no english.
http://en.wikipedia.org/wiki/Demographics_of_New_York