What is vocal booth?
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.
Booth lighting is usually low, which is why print size that seemed fine at the desk becomes unreadable after an hour of takes.
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.
A display that shows text scrolling at reading speed so a performer can read it while looking straight ahead. In music production it shows lyrics near the microphone instead of a script near a camera.