For nearly 400 years, forms of get have been used with a following past participle to form the passive voice: She got engaged when she was 19. He won't get accepted with those grades. This use of get rather than of forms of to be in the passive is found today chiefly in speech and informal writing. In British English got is the regular past participle of get, and gotten survives only in a few set phrases, such as ill-gotten gains. In American English gotten, although occasionally criticized, is an alternative standard past participle in most senses, especially in the senses “to receive” or “to acquire”: I have gotten (or got) all that I ever hoped for. Have or has got in the sense “must” has been in use since the early 19th century; often the have or has is contracted: You've got to carry your passport at all times. The use of have (or has) got in the sense of “to possess” goes back to the 15th century; it is also frequently contracted: She's got a master's degree in biology. These uses are occasionally criticized as redundant on the grounds that have alone expresses the meaning adequately, but they are well established and fully standard in all varieties of speech and writing. In some contexts in American English, substituting gotten for got produces a change in meaning: She's got (possesses) a new job. She's gotten (has aquired) a new job. He's got to (must) attend the wedding. He's gotten to (has been allowed or enabled to) attend. The children have got (are suffering from) the measles. The children have gotten (have caught) the measles. The use of got without have or has to mean “must” (I got to buy a new suit) is characteristic of the most relaxed, informal speech and does not occur in edited writing except in representations of speech. Gotta is a pronunciation spelling representing this use.