DD has been exposed to 3 languages since birth. English from me, my DH's native language, and a third language, which I speak fluently but am not a native speaker. At home DH and I speak a mixture of English and his language with each other. We each speak our native language exclusively to DD (although I speak sometimes with her in Dh's language because I figure she'll pick up English easy enough). The third language I've never actually spoken with her but she's been with me in a number of situations where I speak it and I'm thinking of joining a playgroup with other speakers just to keep up my skills more than anything else.

Anyways, I was completely normal with language skills and DH was late (even though we are both gifted) so we really expected DD to be a late talker, especially with being bilingual and all. However, she started talking at 6 months. So far all her words have been in English (with the exception of saying daddy in DH's language) but she can clearly understand commands in both languages. She mostly gets confused when she hears me talk in the 3rd language so I don't think she's really had enough exposure for it to sink it yet.
HTH