Not specific to accents, but a burlesque accent is a possible term. Definitions include “A ludicrous or mocking imitation” and (in other dictionaries) “intentionally broad for comedic effect”.
PS- Channel surfing an hour ago I came across the Steve Martin version of Father of the Bride in which Martin Short (as “Fraunk”) has this type of accent.
There is always the robot/alien du jour can not speak with contractions dialect.
The jägers are my favorite spear-carriers.
“Gorb. Dis iz turnink into vun of dose plans . . . Hyu know–de kind vere ve keel everybody dot notices dot ve’s killin’ people?”
“It is?”
“Uh huh. And how do dose alvays end?”
“De dirigible iz in flames, everybodyz dead an’ I’ve lost my hat.”
“Dot’s right. Und any plan vere you lose you hat is?”
“A bad plan?”
“Right again!”
Funny - I always thought that her mother had an accent that sounded something like a cross between a nurse, first officer, and a ship’s computer.
Whatever it is, she talked exactly the same way when she appeared in a Babylon 5 episode as the Centauri seeress Lady Morella. (BTW, y’ever notice that not one other Centauri talks like Londo Mollari?)
Obviously, the Mollari are from the eastern continent, while all the other Centauri we see are from the western continent…
Oh, by “she,” of course, I meant Majel Barrett.