"Automated Dialog Replacement"or something along those lines--also called "Looping" and "Dubbing"--is the process of recording actors lines in a soundbooth after filming has been completed. This is often employed if the audio on set was not satisfactory.

The process consists of setting the actor in front of a mic and then "looping" the video clip that corresponds to that line of dialog until they deliver the line in sync with their lips.