gotten

Most Australians, at least, those of an older generation, will react as negatively to gotten as they do to the spelling color.  They regard both as hateful Americanisms.  But so often it is the case that the words that we regard as markers of one particular English have actually been in English English at some particular point in the past.  This is true of gotten which in Middle English —  Chaucer to Shakespeare — was regarded as a simple variant of got and caused no offence to anyone.  Indeed, as gotten declined in British English there were pedants who regretted that now there was no distinction between got the past tense and got the past participle, and who argued that gotten had served a useful purpose, followed the pattern of eaten, driven, etc., and sounded more euphonious.

This was the situation as American English developed until the late 1800s where suddenly gotten (which had been there but on the sidelines) made a comeback.   It is argued that there is a distinction between got the past tense for a completed action and has gotten, the past tense with have and the past participle, indicating a continuing action. He got the prize. He has gotten wealthy over many years.  But I wouldn’t push this too hard. He has gotten the prIze and he has got wealthy over many years are also possible.

The OED is still very firm on the ruling that got is British English and gotten is North American English and indeed, Google Ngram produces no examples of gotten in British English in a corpus starting in 1800.  But in Australian English I am not so sure.  We have got the idea from the Americans and have slowly gotten used to it.