Fully local voice AI on iPhone

I'm self-hosting a totally free voice AI on my home server to help people learn speaking English. It has tens to hundreds of monthly active users, and I've been thinking on how to keep it free while making it sustainable. The ultimate way to reduce the operational costs is to run everything on-device, eliminating any server cost. So I decided to replicate the voice AI experience to fully run locally on my i, and it's working better than I expected.