Also, if you like this kind of interactive thingies, you might enjoy the explorables subreddit: https://www.reddit.com/r/explorables/
for example, I would love to be able to refer to this when watching Erik Singer describe accents: https://www.youtube.com/watch?v=NvDvESEXcgE
Some require co-articulation and diphthongs. For example, "why" requires putting the tongue to the top left, /ɯ/, rounding the lips, making it /u/, then quickly releasing the lips and moving the tongue to the bottom/bottom-right, /a/, then sliding it to the top right, /i/, so that you end up with /uai/ which is pretty close to the correct English /waɪ/.
As somebody else noted, wisely so, I'd love this as a free VST DLL. Could fit right in over at KVR Audio.
"Ben, do you think we can implement this feature successfully in time for the client demo?" "Ahhhuhhhuhhahhahuhuhuhhhuh!"
Funnily enough, the port I did was so brainless that the last bit (the perlin noise part) was originally in C, then ported by HN's very own josephg. I didn't notice this, even though Joseph was a friend of mine at uni. Once I finished the port and went to making sure all the licensing stuff was fine I noticed this all.
but never got around to it. This is great!
Also you should be able to synthesize a raspberry by dragging the tongue out between the lips.
I've been creating a speech synthesiser recently and it does seem like simple approaches produce a voice that is more passably 'male' than 'female', even accounting for the pitch. Aspiration added with white noise sounds better but doesn't quite get that breathy quality across. I think more sophisticated techniques may be needed.