TalkVox

Well... It's not quite a dev kit, but I'm sure you get the idea.

After researching various combinations of processors, microcontrollers, and the necessary support IC's, I tentatively settled on using the ESP32-PICO-D4. It has integrated Bluetooth and WiFi (along with most of the required components for it) as well as some ram and flash and some other stuff. To be completely honest, I have only the vaguest idea of whether this will be an sufficient to implement all of the project goals.

Nonetheless, a while ago I ordered the ESP-WROOM-32 module, and it finally came in. As far as I'm aware, the module matches the pico-d4 version quite well in terms of specs, so it should suffice as a very cheap development platform.

Additional thanks go to Demetri Katsilometes for excellent photography.

A very important piece of the device recently came in: the retainer. My orthodontist took a 3D scan of the roof of my mouth and very generously created a low profile clear aligner with the palate area still intact. Needless to say it fits perfectly, and appears to have a thickness of less than 2mm, which allows for maximal space utilization.

As an aside, I found the process used to create this to be quite interesting. The scan was first 3D printed to obtain a mold, over which a piece of plastic appears to have been vacuum formed. 

Compliments to Dr. Crawford for his work, as well as Demetri Katsilometes for excellent photography.