
--Joe Morgenstern in the Wall Street Journal, 5-19-99 (cited in Wikipedia, Jar Jar Binks).
Butterfly McQueen, eh? That got me thinking.

When the pregnant Melanie goes into labor, with Atlanta burning around them, Prissy shuffles off to fetch the doctor at Scarlett's orders. She lolligags her way back to report that the doctor is too busy with the war wounded to come.
Scarlett tells Prissy she'll have to help deliver the baby; whereupon Prissy shrieks hysterically, "I don't know nothin' about birthin' babies, Miss Scarlett!"
Uh huh.
We all know you can't take these movies at face value.
I don't buy for one second that Prissy is stupid or inept.
No. She is lying.
Prissy's mother is a midwife, for god's sake, and she grew up on a plantation. She knows how to birth babies.
She is engaging in the classic ruse of the powerless and oppressed--pretending to be stupid and resisting by moving slowly. What she's really saying is, "I don't dare stick a knife in you, but I'll be damned if I'm going to help you survive."
Applying this to Jar Jar Binks, I suspect that s/he was an agent of the Dark Side. Not even George Lucas knew.