Mispronunciation by accident or by design
As a follow-up to my nu-ku-lar post, see this from Dean Esmay, on mispronouncing words as a sign of intelligence. Dean is speaking especially of words a person has only read rather than heard--certainly not the case for Bush and "nuclear".
But it's interesting; Dean offers a long list, and his commenters add a few more, as well as the name for the phenomenon: orthographic pronunciation (although nowhere on the thread do I see one of the most common pronunciation errors in the English language: impotent, pronounced "im-PO-tent," rather than, "IM-puh-tuhnt").
I've been tripped up by the following odd ones: my mother once used the word "dour" and pronounced it "dure," (rhymes with "sure"). I was dourly sure that she was wrong, but when I looked it up, it turns out that her pronunciation was actually the preferred one! I guess you should always listen to your mama--
And then one day my brother referred to those fruits and vegetables in the store as "PRAH-doose" rather than "PRO-doose." Certain he was wrong, I looked it up and--lo and behold!--the guy was right. Bummer.
And then there are those who purposely mispronounce words as a sign that they are members of the elite. The link describes how this occurs in Wolof society, but I think it also occurs at times in the West. I seem to remember reading that the great Winston Churchill purposely mispronounced foreign words, a sort of British upper-class marker of the times.
Unfortunately, I can't find a link to back this up, but my recollection is that the idea was "we're British, not French (or Spanish, or what-have-you), and proud of it, too! So we'll pronounce Don Quixote the way we want to, which is like it reads in English--'Don Quicks-oat'-- not the way those garlic-eating (fill in the pejorative expression for foreigners) do. So there!"