I'm hoping you an help me trial a speaking resource hosted at www.mooec.com
After teaching IELTS in Brisbane for over a decade I've come up with a free application to help students with pronunciation challenges, especially Thai, Chinese, and Vietnamese learners. In classes of up to 18 students I rarely have enough time to teach pron individually, and this was my answer
Basically the methodology is experimentation, just as in natural language learning. However as an online resource the feed back is given by a visual image of the user's voice, so if they are modelling a word, they get to see the wave form and compare it to a model. The difference between 'b' and 'd' is fairly easy to see. In fact I think about 65% of pron problems could be helped with this.
In terms of IELTS speaking, there are sections on stress, timing and rhythm, and chunking for different language groups.
The resource is also very similar to the old Ship or Sheep book, which I used to use in EAP classes, in that students listen to sets of minimal pairs to improve their ability to distinguish phonemes. There about over 1200 audio files,
After 5 months in development, the app still runs better on some browsers than otherr.
I'd be interested to know what you think and any bugs you find. The Mandarin page is at Speaking English for Mandarin Speakers