So, what is looping exactly?
Looping is adding background voices and dialogue in movies, TV, video games, commercials and animation. It’s what you call Group ADR or Additional Dialogue Recording.
It’s required when the original vocal audio needs to be fixed or vocal audio needs to be added, be it dialogue (dubbing), efforts (sounds of fighting, kissing, heavy breathing, for example), walla (crowd sounds, etc), and much much more. ADR is also useful when a character’s intent needs to be changed. A looper can change the emotion behind a character simply by changing the words or phrasing originally recorded.