Palin comes across that way mostly because of her accent and speaking style. It reminds me of the way people spoke in the movie "Fargo" She also has a high pitch to her voice. Dropping the g's is fine when making an unserious point, but in serious conversation about policy it doesn't work well.
Palin is crafty and she is smart but is in a way somewhat responsible for the impression people get.
I was thinking about this the other day when I heard Haley Barbour talking. I bet the left and the East Coast folks think he is like Boss Hawg.LOL
Blanche Lincoln isn't much better.
Funny how it didn't seem to bother the left with Kennedyspeak. That was pretty awful. Cuba was Cuber.
It is not just Palin’s speaking style or accent, it is also her choice of vocabulary. She seems to have a limited vocabulary in most interview settings.