The issue is that it is very difficult for adults to learn new phonemes (individual units of sound that distinguish words from each other) - an adult hearing a novel phoneme tends to map it to one existing in their native language.
Children however aren't handicapped by this problem -- they actually learn the phonemes of their language before they understand the words.
In the Mandarin context, this means it is difficult to learn the ü sound - it just is perceived as something like "u" (resulting in inability to distinguish lü from lu). Tones are another category, where it is just plain hard for adults to distinguish words by tonality. Needless to say, production of the novel sounds is also incredibly hard.
Point being - it's difficult to bridge this gap - and I'd imagine near impossible for most without a teacher. I find Pimsleur's claim of learning a language "effortlessly" with a "near-native accent" - with only the aid of a CD - absurd in this context.
A source that goes into this: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2846316/
E.g. the ü sound is https://en.wikipedia.org/wiki/Close_front_rounded_vowel , which means that it only differs from https://en.wikipedia.org/wiki/Close_front_unrounded_vowel (the English ee sound) by the lips being rounded instead of unrounded. English also has rounded vowels, for example https://en.wikipedia.org/wiki/Close_back_rounded_vowel (the oo sound). So you can learn to consciously pronounce ü by pronouncing ee and then rounding your lips as when pronouncing oo while keeping the tongue in the ee position.
Most teachers don't know enough about phonology to give that kind of explanation. My Mandarin teacher certainly didn't. I can only credit Wikipedia with helping me perfect my pronunciation to the point where I can be mistaken for a native speaker on the phone.
This is accurate, but it's worth pointing out that infants are born recognizing every potential phoneme, and what they learn to do is to ignore the differences between sounds that their language considers equivalent. They don't learn to make distinctions they weren't formerly able to make. (This supports the idea that learning foreign sounds is much harder for adults -- I mention it because most people intuitively believe that things happen the other way around.)
Adults do preserve the ability to learn to ignore the difference between two sounds, but that's much less useful than learning a distinction would be. :(
> Tones are another category, where it is just plain hard for adults to distinguish words by tonality.
English features tones pretty heavily, most prominently in the usually-obligatory tonal marking for yes/no questions, but interestingly also in the I-don't-know tonal sequence.
> I find Pimsleur's claim of learning a language "effortlessly" with a "near-native accent" - with only the aid of a CD - absurd in this context.
Agreed.
Interesting, I've some previous and am currently in a situation where I actively correct a child learner, and they respond well to that correction wrt language, less so in behavioural aspects unfortunately ;o)
For clarity, what I do with mispronunciations is break down the word in to phonemes. Yellow is a classic, that a lot of kids struggle with, current child subject has a propensity to say "lellow", though he gets it right more often than not now (age 3) -- I break that down as "yuh-ell-oh" and have him say other words that he can pronounce like "yes" and "yum". So I go "yes, yes, yes, yes, yellow" whilst he listens, then we do it together.
Most early language acquisition is done at home, and for us that has meant away from other parents so I'm not really sure how others do it. I have seen the "aw that's cute" reaction to mispronunciation in the wild, which I guess is a blocker for some.
In the environment of evolutionary adaptedness language acquisition would not primarily occur in a nuclear family, children would spend a lot of time around not just their immediate family but also with other nursing mothers and children close in age and as they get older with children close on age more generally. They pick up pronunciation from the environment and all the other elements of a language too. This is why children will reject a language spoken only by one person in their environment starting around age three[1] and how you get distinct school/social class accents, like international school English or public school English in the U.K.
[1]http://www.todayifoundout.com/index.php/2012/08/a-man-once-t...
This guy spoke only Klingon to his son for the first three years of his life. The same rejection occurs with natural languages if only one person speaks it to a child so if you want your child to grow up bilingual they better hear your language from other people too.
One of the points made in The Language Instinct is that children pick up their languages without using any explicit feedback. That is, people in the child's life who can already speak are liable to ignore errors in the child's speech, and when they do point out errors, the child will essentially always ignore the feedback.
But I wouldn't say children don't get feedback at all. They get a lot of important feedback, such as whether the thing they wanted to happen when they spoke did happen, or whether the person they were talking to appeared to understand them. However, this kind of feedback is generally not the kind provided by a "teacher"; everyone automatically provides it.