Wiktionary
n. A schoolroom equipped with audio equipment so that students may hear and practice speaking a language they are learning.
Wikipedia
The language laboratory is an audio or audio-visual installation used as an aid in modern language teaching. They can be found, amongst other places, in schools, universities, and academies. Perhaps the first lab was at the University of Grenoble in 1908. In the 1950s up until the 1990s, they were tape-based systems using reel to reel or (latterly) cassette. Current installations are generally multimedia PCs. The original language labs are now very outdated. They allowed a teacher to listen to and manage student audio via a hard-wired analogue tape deck based systems with 'sound booths' in fixed locations.
Usage examples of "language lab".
In the meantime it might be a good idea for you to study the regular lessons and spend more tune with the tapes in the language lab.
In a language lab two boys were horsing around until they saw us and disappeared fast.
A trim female lieutenant wearing White House insignia on her olive green fatigues beckoned him out of the lunch line-up on the language lab's mess-deck and took him through the usual obstacle course of card-controlled turnstiles and elevators to their leader.
Then she took me into a room that was like our language lab at school, and I got to wear headphones and I was kind of excited, thinking there'd be a movie.