Onionphone is a native Android application for anonymous, end-to-end encrypted push-to-talk voice and text communication over the Tor network. No servers, no accounts, no phone numbers — your .onion address is your identity.
Cross-platform compatible with Terminalphone — call between Android and Linux/Termux using the same protocol.
Optionally use your connection as a relay for ephermeral group channels.
Find the release page for version 1.0.2 which supports custom bridges for accessing censored networks.
Probably a bad idea to congest the limited bandwidth of Tor with voice chat.
Plain speech can be compressed pretty well. I'm not an expert by any means, but I suspect latency would be the bigger issue.
Latency is a huge issue, but it goes away with the PTT model. I tried full duplex on initial prototyping but it was trash.
PTT solves this by simply forcing the listen, digest, then respond. You can expect about 2-3 seconds of delay from when you release the ptt, to when the other side hears it.