hah! A little bit o EH goes a long way, eh?!  Nope..not native, but been there  bunch of times! Half wanna move there! 
  
Thanks G! 
  
Ok Mummmbles...  I worked at Sony Music International on Madison and around 55th Street in NYC. I was the PC Supervisor there and a consultant. The boss gave us all walkie talkies, so ...he'd yell at us most of the day, etc. etc. Usually the guy would call us in and scream/curse/whatever. I'd usually clam up at that point. It was the 'ol, "HEY, WTF#@$%@#$^ about that @#$^!! DID YOU #@$%^#^ DO?!" And I'd kinda er...mummble. So he'd yell louder, "Stop Mummblin!" Eventually, he'd just start calling me mummbles - "Hey, mummbles, get in here!"  
  
So me, the MAC supervisor, and another guy started playing oh heck...was it DOOM 3D? I forget. This was...1996 maybe.... and we had to name our characters.... so of course, I was Mummmbles - I threw in the extra m for MORE mummmbling. It stuck. I've been using it ever since. 
  
And there u have it! 
  
Mummm