As for the aks for ask switch, I've observed this almost entirely among US blacks. I've also heard people use a short a, while others use a long a when saying "ask." Who says which?

In the UK, axe for ask is invariably an African Caribbean usage (or whatever the new version of Afro-Caribbean is), I used to hear it a lot when I lived in London. I also heard if from Southern Black Americans (again, I'm not sure of their current self-definition) from my days of working on the musical "One Mo' Time" (what joy!), I picked up a lot of useful language, most of it unrepeatable. At that stage realised that there were some words that were not OK to be used by a mere "honky" even in jest. Anyone for the black bottom?