I've always understood 'Get' signified 'the offspring of,' and 'Git' was the South-Eastern-English pronunciation of it. Dahn Sowf the pronounce ALL their vowels wrong, of course. :-)

And yes, Kiwis do, too. I call it 'The sucks-sacks-sex syndrome.'   But of course, everyone speaks English with an accent, whilst proclaiming stoutly that they don't.