Noperf
I go with BASIC as an introductory language.
I cut my teeth on a Commodore 64 and whatever version of BASIC it had (can't remember), followed by a C128 with Commodore's BASIC 7 plus the option of running CPM and whatever was available on that. BASIC 7 suited me.
Yes, it is easy to become sloppy and unstructured in BASIC, but with a little discipline, a little reading, tutoring and constructive criticism I think BASIC is a great way to be introduced to programming. I occasionally dabble in QuickBASIC which lends itself to better structure than the aforementioned BASICs that I've played with.
QuickBASIC is DOS-based and is very limited graphics-wise, given Windows graphics standards. But it is a great environment in which to learn to think like a computer - sounds bad, but I think it's essential for a programmer.
When the limits of an easy language such as this are reached, move on to something else - Visual Basic or whatever, and so on, at whatever rate suits the 11YO.
Personally, I don't think he/she needs to get too esoteric too soon. Write something, get some early rewards, learn and move on.
AA