A、Their learning strategies. B、How much they already know. C、Their feeling about making errors. D、Many variables that vary with

M: Today we have Professor Snow in our studio. (1)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: (2)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. (3)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. (4)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. (5)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.
1. What does Professor Snow do?
2．What’s Professor Snow’s opinion on critical period?
3．What causes the advantages and disadvantages of older second-language learners?
4．Why are older learners faster second-language learners?
5．Why can younger learners function better in certain social interactions?