[guybrushT]

As a father, and as someone interested in this discussion (about "child learning to talk"), I think you will love Prof Deb Roy's insights into how his infant son learned language.

http://www.ted.com/talks/deb_roy_the_birth_of_a_word?languag...

As one of the other commenters pointed out - it is like a tree (words/concepts) branching out from one another. I would be fascinated by seeing if this research can be continued into adulthood, where the individual "concepts" aren't as important as the interplay between them.