According to Prof. Snow, which of the following statements is INCORRECT?

M: Today we have Professor Snow in our studio. She’s an expert on language education. Well, do you believe that the critical period for language acquisition affects one’s ability to learn a second language? Might it affect the way in which one learns that second language?
W: The evidence clearly demonstrates that there is no critical period for second-language learning, that there is no biologically determined constraint on language learning capacity that emerges at a particular age, nor any maturational process which requires that older language learners function differently than younger language learners. There are, however, myriad differences between older and younger learners that play themselves out in second-language learning just as they do in the learning of a musical instrument, a sport, or nuclear physics. For some aspects of learning, older learners have compelling advantages; for others, they have disadvantages. Those advantages and disadvantages emerge as a result of many variables that vary with age. These variables include how much one already knows, how strategic one’s learning can be, how embarrassed one is about making errors, etc., and are not biologically determined.
M: Could you offer any potential explanations for the fact that older learners of a second language typically achieve basic proficiency in the new language more rapidly than younger learners?
W: Older learners do have many advantages. First, they already know one language, sometimes more than one, quite well, and have therefore practiced with the linguistic capacities that speed language acquisition. Second, they are typically better at intentional learning. In other words, they have study strategies, literacy skills, and other resources to utilize. We are not surprised that older learners are better at algebra or history; we should not be surprised that they are faster second-language learners.
M: Are some second-language skills more naturally acquired by younger learners than by older learners? Is the opposite ever true, that is, do older learners acquire some skills more readily than younger learners?
W: It is hard to understand what one means by "naturally acquired." Younger language learners, like older ones, work hard and struggle while learning. But younger learners are probably more willing to learn socially useful language, including phrases and longer utterances, without knowing exactly what it means. Thus, they can sometimes function better in certain social interactions. Younger learners generally are learning in the context of more contextual interactions; therefore, they may have advantages in picking up the meanings of the words they hear. And, while younger learners certainly start out with a "foreign accent" just like older learners, they may be more willing to experiment with unfamiliar sounds and sound sequences.
M: How different would you imagine the learning of a second language to be, comparing older and younger learners? When might changes in learning style begin to take place?
W: One of the pieces of evidence that most strongly argues against the existence of a critical period for the acquisition of a second language suggests that there is no particular age when the ability to learn a second language declines. A critical period would be associated with a rather sharp fall-off in speed, ease, or success of second-language acquisition, but no such decline has ever been reported. Furthermore, studies that have compared the errors of older and younger learners who learn in similar contexts have found they make very similar errors, suggesting again that they are applying quite similar cognitive processes to the learning challenge.
M: Do you have any possible explanations for the achievement of adults who demonstrate exceptionally strong abilities to learn a second language?
W: Studies of highly successful adult second-language learners suggest that they have a high motivation to learn the target language, and a period, typically early in the acquisition process, of full immersion in the target language, with minimal recourse to the first language. Of course, it is more often children who learn second languages that find themselves in this position of being highly motivated and left to sink-or-swim in the second-language setting. Consequently, it is perhaps not surprising that they are somewhat more likely to achieve high second-language proficiency.
M: What influences in second-language learning would you say are repeatedly overlooked by the researchers who conclude that children demonstrate a greater capacity to learn a second language than adults do?
W: The missing variable in research on age differences in second-language acquisition is first language maintenance. Child second-language learners are somewhat more likely to achieve native-like proficiency in the second language than adult learners, and massively more likely to lose proficiency in their first language in the process. Adult second-language learners almost never become monolingual in the process of learning a second language, as children often do. Thus, they master the greater cognitive and linguistic challenge of maintaining two languages, often at a very high level, with much greater success man children do.
M: Well, thank you Professor Snow.
W: My pleasure.