Infants and language

Thanks to both Jeff and Gabi D. for this one:

Jeff: This is a TED talk about the linguistic capabilities of infants, how they adapt to the languages that they hear, and how that relates to why it is so hard for high school students and adults to learn a new language.

Gabi: This video discusses the process by which babies learn new languages. It specifically deals with babies in the period when their ability to learn language is highest and when their brains are most malleable. I found one part to be particularly intriguing, in that the result of the test, in terms of data, can imply many different things. The test where English-speaking babies were exposed to Mandarin for twelve sessions and then compared to babies who were exposed to Mandarin for ten months was fascinating. First of all, why would the human brain be so inefficient that nine months of extra Mandarin practice would not differentiate the skill level of a speaker? If we assume that the human brain isn't so inefficient, could that indicate that being able to tell sounds apart is just such a basic task that it takes almost no time to master, and thus studies should check more advanced linguistic functions when further examining this topic? Also, is the baby exposed to both languages actually learning two languages, or just becoming confused? It seems that the video indicated that the baby is storing two sets of language data, which means he is learning two languages. This seems possible because the brain of a baby is so flexible. Also, although babies have almost no use for learning two languages simultaneously, we know that grown humans can, and that ability must exist during infancy because our language skills decline sharply afterward. Overall, scientific evidence makes it clear that the baby's brain is a language-learning juggernaut.