Nature Reviews Neuroscience offers the full text (HTML and .pdf) of this interesting overview to language development in its November issue:
Patricia K. Kuhl. Early language acquisition: Cracking the speech code. Nature Reviews Neuroscience 2004. 5: 831-843.
Institute for Learning and Brain Sciences and the Department of Speech and Hearing Sciences, University of Washington, Seattle, Washington 98195, USA.
Infants learn language with remarkable speed, but how they do it remains a mystery. New data show that infants use computational strategies to detect the statistical and prosodic patterns in language input, and that this leads to the discovery of phonemes and words. Social interaction with another human being affects speech learning in a way that resembles communicative learning in songbirds. The brain's commitment to the statistical and prosodic patterns that are experienced early in life might help to explain the long-standing puzzle of why infants are better language learners than adults. Successful learning by infants, as well as constraints on that learning, are changing theories of language acquisition.