This website was created to help people improve their American English pronunciation. At the core is a series of videos explaining in detail how each sound is created, as well as a blog.
If you want more information on the photos in this video, which have parts of the mouth drawn in, see this video on the parts of the mouth.
How to make this sound:
This video compares the 'ee' as in 'she' sound with the 'ih' as in 'sit' sound. If you are not familiar with those videos, I suggest you work through them before this blog entry.
Take a look at how the mouth position changes on the different vowels:
How to make this sound:
Video Text: