What is talkback?
The control-room microphone that lets an engineer speak to the performer in the booth. Every talkback interruption ends a take, so anything that reduces the need to explain where the song is speeds up the session.
Listen back to raw takes from a paper-based session and you will hear how many stops were purely about lyrics rather than performance.
An acoustically treated space for recording voice, isolated from the control room. Because it is isolated, the performer's only sources of information are the headphones and whatever screen faces them.
Building one final vocal from the best parts of several takes. The editor chooses per line or per phrase and crossfades between them, which is far quicker when every take was sung with consistent phrasing.