Ironically (or pseudo-ironically?), the very difference in connotation between self-taught and autodidactic is pretentiousness. Perhaps not quite pretentiousness, but more of a difference in social class -- a self-described autodidact is indicating that even though they are self-taught, they are not "blue collar" self-taught.
And it's not that self-taught always means lower class, it's just that autodidact always means higher class. There must be a better word in English for the type of distinction in words I am describing here, maybe someone can enlighten me...
Um, fuck you. Really, I mean it. My mom, a single mother, worked full time doing hard physical labor in a bakery. Her back is still sore from all the hard work she did to raise me and my brother. We lived in cheap housing, paycheck to paycheck for years, and went to pretty crappy public schools. I don't see how you get anything about economic class from the word I used.
We were poor growing up. I liked to read. I learned big words when I read, and I use them when I communicate. End of story.