Slow Chinese, as far as I know, is the first site to do this (and just this) for Chinese. I know that the same “slow” concept has already existed for some time for learners of German (Slow German), and that it is quite popular among that learner community. The idea, of course, is that if learners are exposed to enough slowed-down input, they will not only get better at recognizing the words they know, but will also be able to more easily pick out the words they don’t know, and the gains will gradually transfer to normal-speed input.
The linguistic question, of course, is: does this work? Is it a good idea?
First I’ll quote friend and fellow linguist JP Villanueva on what he once said about slow input:
Listen to me: slow input does NOT help you learn language. No! NO NO NO. At best, slow input helps you learn SLOW LANGUAGE. [...] Whenever you get mad at someone for “talking too fast,” you need to remind yourself that you don’t speak that language, and no amount of SLOW is going to help you understand.
Counter-intuitive? Remember when you learned to ride a bike, and you found that it was easier to balance when you had a little speed? Remember when you first learned to drive, and you realized you had more control with a little speed?
Same with language. Slow speech doesn’t help your memory. You don’t need every word in a sentence in sequence in order to understand what someone is saying.
Besides, that’s not how your brain listens to your own native language, anyway. Your brain listens for semantic landmarks and then fills in the information in between. You need to learn to do that in your second language. Slow speech levels semantic landmarks, and over-emphasizes the non-content words that hold sentences together.
When it comes to Slow Chinese, there are actually two relevant questions:
Is slow input valuable?
Is slow input for news (or other media intended for native speakers) valuable?
In answer to question #1, I’d say yes. JP knows what he’s talking about, but earlier in the same post he also made a few caveats where confidence is concerned, and with good reason. There is a period when a beginner has a really tough time distinguishing the sounds of the target language. Yes, the purists are right when they say that continued, persistent exposure can overcome this obstacle, but most learners are not so hardcore. They’re emotional and easily discouraged. They want some help beyond “don’t give up,” and slowed-down input can provide that much-wanted crutch. It is a crutch, however, so if used, it should be withdrawn as soon as possible. It is most useful for learning the phonetics of the language as a beginner, in individual words and short phrases.
In answer to #2, I’d say no. If a learner is ready to take on media intended for native speakers, he should already be comfortable with the language at natural speed. If he has the vocabulary to take on the media but can’t handle the speed, it is likely because communication as a learning goal has been neglected. One can’t carry on normal conversation without comprehension of speech at a normal rate (unless one limits one’s conversation partners to slow-talkers only). So it seems to me that one would be tackling slow-speed media instead of tackling normal-speed listening comprehension and communication, which under most circumstances is a big mistake.
So my conclusion is that the learner’s time would best be spent working on simpler normal-speed input to improve listening comprehension (for Chinese, most Elementary and Intermediate ChinesePod dialogues are good for this; users can listen to the dialogue-only audio, all of which also have transcripts), and then later tackling normal-speed media.
Still, enthusiasm for learning is a valuable thing, so if Slow Chinese is what you’ve always wanted, I say go for it. (Plus, it’s free!) Just don’t forget that it’s not likely to help you out with conversational fluency, if that’s your goal.