Fair enough; your last sentence was a reasonable answer to my primary question, since I'm not sure I could differentiate natural vs constructed dialects (I'm to

Fair enough; your last sentence was a reasonable answer to my primary question, since I'm not sure I could differentiate natural vs constructed dialects (I'm tone-deaf enough to have trouble with truly foreign language accent identification) so I err on the side of giving people the benefit of the doubt that it's not malicious, however it seems you were referring to more obvious imitation which I can't speak to, and have to trust your judgement on. And to your middle question, self segregation of direct interaction doesn't necessarily limit exposure. We sat in the same cafeteria, went to the same classes, rode the same busses, so it seems natural that some aspects of speech cross pollinated out of peripheral immersion. Take "jawns" for example. I'm pretty sure I first started hearing it in... 4th, 5th grade? Had _no_ idea what it meant or the implications of using it, but used it because the people around me used it; nothing more sinister or subversive than that, frankly I don't think I had the social sophistication to motivate that sort of conscious mimicry at that age.