I was searching/browsing my internal SD filesystem and I stumbled across a bunch of WAV audio files for the Google navigation (The audio files that say stuff like "in 400 feet" and "you have arrived"). It seems to be the default, nasty "Pico TTS" audio.
I found these files in /Android/data/com.google.android.apps.maps/testdata/cannedtts/en_US.i.c862f575/
However, in the /testdata/ folder is another folder called simply "/voice" and in it was a zip file called "voice_instructions_imperial.zip". I checked the contents of the zip file and they are all the same navigational filenames, and they say the same phrases but with a much more realistic, more pleasant voice. These files are also OGG instead of WAV.
I attempted a few ways of trying to replace the awful Pico wav files with these files (yes, I also converted the OGG to WAV), but when I go to my navigation the normal Pico voice still plays. Although, I did notice one very strange difference. It pronounced the name of a nearby street differently than it normally does (but still with the Pico voice).
Anyway, most truly decent TTS voices downloadable from the Play store are not free, and if there is a way I can use this other "hidden" voice, I'd really like to. I'm not sure where it came from. It IS possible that it's something left over from a long-since-forgetten past attempt at installing extra voices, but I don't think so.
Can anybody provide any information on this zipped voice package I found? I'd really like to be able to use it if possible.