I love the American Public Media show Krista Tippett on Being.
A few weeks ago she recorded a show with Jean Berko Gleason who specializes in language development. So of course it's about a child's development of language. I loved it and if you get a few minutes to fold the laundry, cook dinner or whatever and listen to it you might enjoy it too.
Linguistics pioneer Jean Berko Gleason says language reveals unexpected truths not only about our human relationships with our world, but also our consciousness of ourselves. You can find the pod cast here
You can also watch Deb Roy's lecture on language development here. At least listen long enough to hear the time-lapse segment on his son's development of the word "water" its really cool.