sentences:  Mumble uses the low-latency audio codec Opus as of version 1.2.4, the codec that succeeds the previous defaults Speex and CELT.This and the rest of Mumble's design allow for low-latency communication, meaning a shorter delay between when something is said on one end and when it's heard on the other.Mumble also incorporates echo cancellation to reduce echo when using speakers or poor quality sound hardware.