Make the little talking sounds that play as dialogue types out, like the text boxes in video games. Pick a voice, tune each character, export WAVs for your game.
The blip every character uses.
Your phone taps along with each blip. Harder taps for angry and shouting, faint ones for sad and sly.
Shifts pitch, speed, brightness and sentence shape.
Pitch, pace and lines for whoever is talking.
A zip with a folder per character, one WAV per mood, and a voices.json with every setting.