Blah blah blah blah. Blah. Blah blah. Blah.... Blah blah blah. Blah blah blah. Blah blah. Blah!
Homo loquax! I remember this from Aldous Huxley.
I googled and found to my surprise, there's tons more:
If you watch the news channels on satellite television you'll understand what I mean by 'blah blah blah' - endless talk!