DD is 16 months and doesn't say any words yet. I'm not worried because she clearly understand an awful lot of words and responds really well to instructions in both languages. She also uses lots of signing and can use these when prompted in either language. She makes lots of word-like noises and has a conversational rhythm. People have told me bilingual babies can speak later- I'm not sure if this is true or not so would be interested to hear when your baby started using proper words? Plenty of single language babies I know are using a good few already but of course this could just be the normal differences in development rather than related to bilingualism.