Unlike some of the behind-the-scenes footage in which Peter Mayhew is just speaking his lines as filler, this seems more like the character speaking his dialogue "in character." I'm reasonably sure this was never meant to be part of the film itself, but it's still a curiously finished segment that shows Mayhew was committed to the character, even when his lines were going to get replaced completely by the yowling noises we know today.
