Murloc's "meow" is extremely rare, as he only says it when he is desperate. Without serious business or goals, he doesn't meow, preferring to get the message across using body language. Overall, Murloc is a very quiet kitty, and the only thing he does loudly is running for greeting guests. He even purrs silently, and only when there's a good reason.
Yolka, on the other hand, is in a very hooty mood. She hoots in responds to my words, so it doesn't go on for the whole night - only while I'm filming. When I'm silent, so is Yoll.