Why do accents in speech occur?

Question

english accent, australian accent, Texas, Boston, etc...

Answer 1

First, there isn't AN English accent, there's gabunches of them.

A population that's isolated (which most have been through most of history) simply develop somewhat different ways of talking, different pronunciations, different expressions.

Sorry, that's not really an answer, though, is it?

Someone comes up with a really choice expression, and others near them pick it up and hand it down. That's one way.

Why pronunciation changes, I'm not so sure.

One reason for regional variation in the U.S. is that the people from England who settled in the north were predominantly from an area with one accent, those in the south from another, with a different accent. Some of these differences have persisted, though also changed somewhat, through normal drift, and the influence of other people settling in the same place.

I believe the Australian accent is largely based on Cockney of lower-class Londoners, who made up a major proportion of English who settled there.

There's a really interesting TV documentary series on this (done in the 80s) called The Story of English, and there was a book of the same name.

Finally, I believe this question has been asked here before. You could search to see what more people have answered.

BTW, when populations are isolated from each other long enough, the differences become enough to call them different languages.

Answer 2

because people are in different places