I'm not, but I know of a couple people who are and their kids seem to know about the same total number of words as other kids their age but because the words are divided between the two languages, they have about half as many as in each language. So, if most kids their age know 20 words in one language, bilingual kids will know 20 words, but about half will be in one language and half in the other.
My husband swears that my son said "mama" while looking at me at 8 months old, but I didn't hear him. I was sure he was saying "dada" at 2 months, though.
His first real, regularly used word was "up". I can't really remember what came after, although he didn't talk much until about 18 months he had about 200 words that he could say if he felt like it. Since then, his language skills just amaze me. He's only 2 1/2 and says things like "It's too difficult." and "The sister should drink the milk and eat the cookies." (from looking at a picture in a book) and for several months now (at least 6, I think) he's been saying "Mommy (or Daddy) I sought of something". sought =though, btw.
I love listening to little ones talk, but it sure can be hard sometimes to figure out what they're saying.