Language theorists have long believed that complex mechanisms are responsible for the language spurt that most young children go through between one and two years of age.  Using computational simulations, researchers from the University of Iowa last year suggested that simpler explanations exist.  These explanations include the fact that children learn many words at the same time, words to be learned are repeated over time, and words vary in difficulty.

More on this story, from 2007, can be found here.