I am new to linguistics, and have just started reading about sociolinguistics. I'm interested in language change and motivations for it. There are three terms that I have come across, but am struggling to create a definition for them, and their differences. Would anybody be able to help?
These are: internal motivations external motivations extra-linguistic motivations.
I understand that internal motivations are linguistic things, like how easy it is for a language to merge with another because of similar features. I've also read that external motivations concern usually involve geographical and social factors. The last is more troublesome. I've heard that it also involves social attitudes and factors, so how is this different to extra-linguistic motivation?
It would also be great if anyone could point me in the direction of studies that relate to each of these. I've been reading Labov's department store study, and how social class dictates if pre-vocalic r's are pronounced. Would this be a study demonstrating external or extra-linguistic change though?
Thanks for any help!