My experience is that a lot of language learning is actually acquisition rather than learning. Like so many things in life you have to just do it and apply some sort of feed-back mechanism, the feed-back allows you make adjustments so that you improve. There is a learning element or appears to be because you increasingly acquire words and phrases but even that is probably overemphasized because eventually when you begin to roll, meaning of new structures and usage is inferred from usage and experience. I almost certainly learned that 2+2=4 but I know that 120+120=240. I learned (kind of) jin1tian1 guo4 de hao3 bu4, but derived from observation that jin1tian1 guo4 de hao3bu4hao3 (今天过得好不好？) means "how has today gone?". Snap! one moment at the right time and the realization that combination of words can be used in this way is owned.
Children acquire many skills by acquisition, they just need the raw materials, the desire to learn and maybe a few holistic suggestions ("keep pedaling", "look ahead" etc.) What they do not need is a complete breakdown of the bike mechanics, laws of physics and a detailed diagram of every physical movement they need to make. It should be simple. For language learning you still need desire, the raw materials are sound and text and surprise surprise, much of the feedback can be applied by yourself, most of the rest by speakers of the language in action.
Many of the adults who approach language learning cannot let go, some are even offended by the concept that they should learn like children. Right from the word go they want to know about aspirated fricatives and complex grammar. Right from the beginning they obsess about the slight differences in pronounciation they hear (which is right?) and soon they will try to apply the grammar rules they learned to real spoken language and squeal in indignation that they are not obeyed. Somehow they have managed to forget that their own mother tongue only loosely obeys grammar rules when spoken in real situations, forget the regional pronounciation variation in their own language etc. etc.
Linguistics does not directly map to language learning. The science of language is important and useful as is the science of physics but I can learn to ride a bike without physics knowledge. Educational institutions have a vested interest in mixing linguistics into their course because otherwise the course material would look rather sparse, and how would they set and mark exams?
Maybe the perfect Chinese course would be like this for the first week.
"Right people here is a whole bunch of Vietnamese, Cantonese, Thai, Japanese and Mandarin audio." Please use it to calibrate your ear to Mandarin language, I will test you on some more audio at the end of the week just to make sure you get it. When you get the feel you can always listen to try to determine where the sentences are, when people might be saying names, what sounds are often co-opted for breathing stops etc. what is the mood of speakers and identify a few common sounds you hear a lot (mimic one or two of these at the end of week, and I will tell you what they mean). Don't worry about meaning for now, but if you think you have guessed something, especially in the video material you can share on Friday. Ok see you at the end of the week, oh and by the way let my know which Mandarin voices you each like the best, we will see what we can do as you are going to be listening to them a lot."
I can't really see a university going for that though but perhaps I am wrong?