Boba is slang for it, but the only place I've ever really heard people call it that primarily is around California.
(I hesitate to call it boba, because boba originated from a.. adult video actress' nickname which means big breasts. Original pearls in Taiwan used to be smaller, but she decided to increase the size and thus some people starting calling it boba)
ALSO to everyone who says they don't like bubble tea because of the pearls... you can get bubble tea without pearls... and also bubble tea without tea. I don't let people off the hook if they say they've only tried bubble tea once and don't like it LOL (It's like trying one smoothie and saying you dislike all smoothies because you didn't like that one flavour)