How to get his family to speak English when they are around me.?

I currently live with my boyfriend, and pretty much most of his family. I am a Caucasian female and my boyfriend is a Hispanic male. Yeah, you probably already figured out the problem already. His family speaks Spanish in front of my a lot of the time, especially when my boyfriend isn't there at the table. The family is really nice and sweet to me when they 'Remember' that I don't speak Spanish. In front of me conversations will be made at the dinner table in Spanish and I will feel completely left out, same goes for in the car. The only time they will speak in English seems when they are 'stuck' talking to me or not talking to anybody at all, or when my boyfriend is around (for the most part). The thing is that I am living with them, and they have been nice, and I don't know how to go about asking them to speak in English without them feeling like i am bossing them around. .. I think it is harder because this is my first time away from home and my family, and now it feels like I have no one to talk to.