The sayings, "where do you stay?" - and - "how?"

People ask me "where do you stay?" when asking where I live. Why "stay"?

Also, people say "how" instead of "why"?

I think it's cool how this quirk happened.

Any other examples?

My gran (long deceased) used to talk about going to "the pictures" when go to see a film...

Anyways, long may these sayings continue :)