In case you missed it, Walt Wolfram did an AMA on Reddit yesterday. The parts relevant to language change/use online:
How do you think technology (and especially the internet) is influencing how language changes these days?
Now that’s a BIG question. Written language can always have an impact on spoken language, and new technologies (like the internet) can certainly increase the usage and dissemination of written language. I think this is a question that Big Data style methods of research will be able to answer as time goes on. Furthermore, some of my grad students have even told me about some research that shows how the QWERTY keyboard layout and typing skills can affect language choices. So it is likely that the tools we use to write also can come into play.
Still, the fact of the matter is that written language is largely a mediated form of spoken language. So I am more inclined to think that while written language on the internet might not have a great influence on spoken language change, the internet and other new writing technologies might help in the dissemination and awareness of aspects of language change that is already taking place.
I should note that Joel Schneier has been my consultant on this question.
Might greater contact between various dialects (and to lesser extent between languages) contribute to greater homogenization of languages/dialects?
While this is a commonly expressed thought, I’m not aware of any evidence to suggest that is the case. Even if the internet can increase contact between language speakers of different dialects, each individual’s spoken language patterns won’t necessarily be completely changed. There might be some new lexical forms, and they might have encountered evaluative information about their language, but I am inclined to think that their spoken language system will be largely unchanged.
Plus, as history shows, language contact and dialect contact do not necessarily lead to homogenization. In fact, they more likely lead to greater and more complex heterogeneity.
Again, Joel Schneier was consulted for this :)
Much more about AAVE, sociolinguistics, and other topics at the link.