Re: When you read a book that contains dialog in a dialect..
YES! Happens to me all the time!
I've just been reading a trilogy of historical fiction based in 13th century England/Wales (Here be Dragons, Falls the Shadow, and The Reckoning by Sharon Kay Penman). Excellent books! After close to 2,000 pages in that world, I find myself constantly thinking phrases like "for certes," "mayhap," and "ere we go..." etc. I've had to stop myself a few times from saying them outloud...
Re: When you read a book that contains dialog in a dialect..
Not usually, however the Outlander/real world crossover is hard for me right now because one of the guys in my department is Scottish, and "will nae" and a few other things I read in Outlander are pretty common to hear, which makes it REALLY hard not to say them when I'm re-reading!
Re: When you read a book that contains dialog in a dialect..
Having just read some books set in Scotland, after meeting someone from Scotland I found myself putting her voice into all the words. I think it shows good imagination!