Reply #53: It's called code-switching

[tishaLA]

and almost all of us do it to one extent or another. When I write on DU, for example, I don't write as I do in my academic life; if I did, people would respond to my posts even less than they do. Similarly, when I am teaching, or talking to my dissertation director, I speak in a different way than I do when I am interacting with people in a bar. People also do this because different kinds of speech (whether speech acts or idioms or whatever) are more effective in different settings.

I don't read code switching as insincere--he did, after all, grow up mostly in Kansas, where dropping the /g/ is hardly uncommon--but that sincerity can have more than one voice, even from one speaker.