Adventures in Observed Phonology

Some teenagers, some British and some not, participating in some kind of summer program that means they are all wearing identical t-shirts, are sitting near me in the cafe where I have decamped to work for the afternoon. (The cafe is air conditioned and the library is not.) One of the British teens is teaching the correct pronunciation of a new word to one of the foreign teenagers. It makes no sense whatsoever in an American accent, so try to imagine it in an estuary-English one: "Y-A-W-N. Yawn. It's 'yaw' like 'you're great' but with 'n' instead of' great.'"