Is the ability to acquire language innate or learned?
I do not think an exact answer to this question for either side exist. The answer lies between middle somewhere. And there are many examples that can justify either side.
Many of my friends are ABCs--American born Chinese, who can speak fluently English but rather Chinese, even though they are ethnically Chinese. Owing a yellow Asian face, black hair, and black eyes, they respond in English when their parents, who are Chinese immigrants, talk to them in Mandarin. As a outsider, I always feel such a scene funny and bizarre, as if two creatures from different planets speaking their own language but somehow they can still have a successful communication without any translation device to help. A mother of an ABC kid once told me， shaking her head, helpless:"My daughter's Mandarin is rather poor, though we sent her to a local Chinese Language School for training, people there don't take it seriously...She can barely remember what she has learned...but she can understand us (her Chinese parents)talking." When I asked the girl to speak Chinese, though not fluently, I can still tell the differences in accent and intonation from other Americans who can speak Chinese. As her mother said, though brought up in America, Chinese future generations tend to master a better sense of Chinese learning, which to me seemed an aptitude for their parents' mother languages. However, such an argument can't stand. If so, Those ABCs should speak Chinese at least as well as English since they parents teach them everyday through daily conversations. They nevertheless speak perfect English as Caucasians which indicates their ability to acquire language is not innate but learned--it is because they are raised in an English-speaking environment that spurs on to speaking good English. The same applies to a kid born in an American and Chinese's family who grows up in China, he is very likely to speak fluently Chinese.
Besides, it's also true that aptitude does have impact on one's ability to acquire a language. For instance, 10 American students under equal condition, taking Spanish class, we can find that each one of them make different progresses and some are good at it, while others not. Since the learning environment is identical, one's innate skill and capacity probably justify the consequences.
Above all, I would like to say how to learn plays a more significant role in acquiring a language than how much talent one gets.
