P.S. The image above is hosted at Wikipedia, and there's one problem with it -- although the upper teeth are labeled "3", there's no number for the lower teeth! How can one explain the articulation of the English th sounds ð and θ without referring to the lower teeth? (Also, there's no convenient way to distinguish between the upper and lower lips, as when discussing the proper pronunciation of English "v" and "f".)

So I've created a new version of the diagram, in which the lower teeth and lip are numbered as 19, 20, 21. Could this be hosted directly at MR, if I email it to the right person?

P.P.S. Is it possible for a moderator to rename this thread Towards creating a "mouth map" of Russ. and Engl. consonants (BETA) (I think this might be more self-explanatory, and after I thought about it, the "Tongue gymnastics" metaphor seemed rather stupid.)