You don't seem to understand the difference between "dialect" and mispronounced words, i.e., "nucular."
GWB grew up in a home with parents from the Northeast who do not have a TX accent and attended Andover ...which last time I heard isn't in West Texas. So, where do you think GWB got the accent you think sounds "dumb."
I think you think dumb.
Yes, I have a TX accent and I'm not embarrassed by it. The last I heard there is no correlation between the rate of speech and intelligence. Too many people get into trouble when their tongue gets ahead of their brain!
So, GWB developed his accent over time. I grew up in Texas and don’t have an accent now, but I did when I was young and thought that was just the way people spoke.
I would not have had a 30+year career in broadcasting with that Texan accent. Nope. Nobody would have hired me.
So who’s dumb?