1Few uses mark out the Americanness of a person more readily than their natural use of got and gotten as alternative past participles of get. (These uses are also spreading to Australia and New Zealand, as some of the examples given below will show.) Gotten is no longer used in Britain (except in ill-gotten), although it was once in regular use. In AmE, it is used only when the meaning is ‘have (or has) obtained or acquired’, i.e. when it denotes coming into possession; when the meaning is ‘have (or has) in one's possession’, i.e. when it denotes the fact of possession now, got is used. The difference can be seen by comparing the two sentences We have gotten an apartment in Manhattan, which means we have recently acquired it, and We have got an apartment in Manhattan, which means we have one available to us (as well as a house in Boston, for example). BrE uses got in both cases, with consequent ambiguity in some cases. Examples:

An army friend…had gotten us tickets for a Tchaikovsky extravaganza

Philip Roth, 1979

Have you gotten your paper the last couple of Sundays?

New Yorker, 1986

I'd only gotten about 4 hours of sleep the night before

weblog, CanE 2005 [OEC].

2Gotten is also used when the meaning is ‘have (or has) become, come, developed, etc.’, i.e. when a notion of progression is involved:

Has my reputation in town gotten that bad?

T. Winton, AusE 1985

This last year and a half I've gotten to fill out a lot of forms

John Updike, 1986

People in the USA have gotten much healthier in the past 30 years

USA Today, 1988

Many shipping companies have gotten rid of their nautical inspectors

Lloyd's List, 2001 (German speaker)

It's strange that I still haven't gotten used to it over the past fifteen years

fiction website, AmE 2004.

3Got, not gotten, is used in the expression have (or has) got to = must; for example, if you say I have gotten to leave this evening you mean you have made arrangements to leave, not that you are obliged to leave.