Thanks to stephanhodges for introducing me to this forum. Long time ago I too studied some Chinese, but alas not enough.... I'm flattered that you have found my site and discussed the chorus method. Admittedly, this is a stone-age method, not an invention of mine, but it certainly has several benefits, many of which can be scientifically corroborated, and many of which I have only understood thanks to my medical training on top of a PhD in speech science. (I have listed 11 "heavy" benefits in my presentation when I give talks about this.)
The main effect why chorus practice is so efficient is due to brain anatomy and physiology:
***First, as most of you have surely experienced, it is quite difficult for untrained singers to sing in a different tune or pitch than the others in a choir. Similarly when you sing-along with friends in a "Happy birthday to you...", etc. And you must have felt the phenomenon when you are listening to someone with a creaky or hoarse voice, whereby you get a strange tickle and strong urge to clear your own throat! These experiences are due to two important neuroanatomical and neurophysiological facts that, of course, also apply to _speaking_ in chorus.
(i) In the vicinity of the speech area in the frontal lobe (Broca's area) there are networks of nerve cells called "imitation neurons", or "mirror neurons". They are important in perception processes by matching input data with our previous experiences ("memories") of saying the same or similar things. The best studied mirror neurons are involved in visual perception. Look it up in Google and Wikipedia, and you'll find amazing reports. (Giacomo Rizzolatti is a grand name.) The most amazing thing to note about these mirror neurons is that they are _motor_ neurons! I.e., they are active when the individual _speaks_. And, obviously, when the individual _hears_ speech, if this speech is in a comprehensible form, i.e., he or she has previous experience of saying like things. Otherwise they don't mirror the input. We all have noticed that as new beginners in a language class, haven't we?!
(ii) Direct neural connections from the auditory center in the temporal lobes to the auditory mirror neuron areas have been found. These connections don't themselves pass via the speech comprehension area (Wernicke's area), so the mirroring processes begin even before the listener is aware of them or of the meaning of the input. These mirroring processes in the brain's _motor_ area will directly influence the speech organs of the listener and enable, or even _enforce_, like magically, a very accurate pronunciation as he or she speaks along with the teacher. So even a "chorus" of 2 persons, or 1 cd + 1 learner, is possible, but I have found that 8 learners is a minimum number for maximal efficiency, and 7 learners is too few; a strange "step function" here. Maybe partly because the loud sound impact of the chorus triggers the Lombard voice reflex that makes us unconsciously speak louder. I don't know the upper limit. "Crazy-English" Li Yang may well be on the right track... At least for his revenues... ;-)
http://www.china.org.../NM-e/83370.htm (I too ought to have been an English teacher in China! Hehe.)
The conclusion from these first facts is that the learners will need lots of listening practice (in active, attentive silence) before they can have a fair chance to imitate. The teacher should solo-repeat the sample sentence (seldom single words) at least 7 or 8 times at a natural rate of speech before the learners are invited or permitted to speak along. Then when they start speaking in chorus, they will have to concentrate on the rhythm of speech, which has been shown to be one of the most important, if not THE most important, factor for perception and thus also for a listener-friendly pronunciation. NB: The teacher too keeps speaking in the chorus, dominating it to "enforce" a natural and correct rate and rhythm. The learners should be encouraged to begin and end synchronously. Initially also to cheat with any difficult consonants and vowels, if necessary. (This is how toddlers do when acquiring their first language! And they never get a "foreign accent" even if they can't pronounce the indivdual sounds; this is so because they have the correct rhythm almost from the very beginning of speech acquisition. Obviously a good idea also for adult learners.) Further on, the language class will alternate fairly frequently between teacher-solo and teacher+chorus. And when some confidence is built up, also learner-soloes. (At most in chunks of 3-4 solo repetitions in these individual-practice-chorus-practice alternations, to avoid embarrassment for those who need more practice time to reach the target.)
***Second, the chorus repetitions (with alternations as above) will have to go on for a great multitude of times. In all other practices for skilled performance, such as athletics, music, circus, type-writing, car driving, surgery etc., it goes without saying that one has to practice many, many times to acquire sufficient skill. Unfortunatly, this self-evident knowledge seems to have gone "out of fashion" in language education since decades ago, and now is almost forgotten. This is where I want to change the current routines. 20-30 repetitions is certainly too few. A hundred may be more appropriate. By the thousands must be better - but we have a limit to our patience and endurance, too, haven't we! But a toddler actually practices his speech much more than thousands of times, more closely to a zillion times. It does take some 5-6 years to acquire the very basic command of one's first language, doesn't it! Fortunately, adults can do it in a single year or less - if given appropriate instructions.
The 146 (!) speech muscles are no different than any other muscles in the way they are run by the nervous system. They have to be co-trained and co-ordinated, in our first language as well as in all our subsequent languages. In learning a new language and speech, we do need lots of repetitions. This is also due to neurophysiology, and specifically to the way neurons connect with one another with _synapses_, as they are called. Buds for new synapses are formed within seconds in a learning situation, and mature synapses within 10-15 minutes. If they are reinforced by repetitious stimuli. With too few repetitions, the buds may regress, and no synapses are permanented, and the time spent on that "pseudo-practice" will have been largely wasted. It has been shown that a new skill, e.g. one sample sentence, can be automated and permanented to perfection in about 15 minutes.
It will have to be repeated the next day, too, and the next, and the next.... But then! Unforgettable! Like we can never un-learn how to drive a car, or walk, or talk, once we have learnt it. In a simile, I say that learning and memory is like walking across a lawn: Paths will form where you walk sufficiently many times. And nowhere else! And all new paths have to be connected with older paths. I.e., we can't learn much without some pre-knowledge; every peice of new knowledge is a variation of old knowledge. Such as *speaking* - we are all super-experts on at least one language, aren't we! All human speech is based on the same fundamental principles, e.g., rhythm, melody, consonants, vowels, syllables, words, sentences, ..., etc., and we all have the same anatomy and neurology, etc. So just tweak it a bit - and voila - there's your new language! ;-)
Phew.... Please pardon my verbosity... ;-) I could go on and on for weeks, presenting one neurophonetic miracle after another! Let this suffice for now lest you flame me for occupying bandwidth, and good luck, everyone!
Olle in Sweden