How do you write the sound murlocs make?

Rwlrwlrwlrwl was used in the video of I am Murloc by Level 70 Elite Tauren Chieftain. I believe they hired a professional murloc to record the sound for the video too.

This is something that can be open to interpretation though, as typing out mgrlllmgrlrrr and mrrglrlrlrmgrrr are always fun and get the point across.