Good advice from Bookworm. Our kid is in an English/Czech home environment, and isn't in school yet so has limited exposure to French. We have CD's with children's songs in all three languages, and she's now starting to mimic the French which is quite amazing. She also picks up jingles off the radio which is very very funny .

I'm no linguist but from experience one of the major stepping stones is picking up the rhythm, intonation, and delivery of a language.

We have an Indian friend who was raised in the Swiss German part but has lived in the French part for some time. She speaks Hindi, Swiss German, German, and French, as well as excellent English (with an Indian accent ). She and her Indian husband have young children- next time I see her I'll ask her how they are approaching this.