Example
The English plural morpheme for nouns has three allomorphs:
(notation in SAMPA)
from: Iggy Roca and Wyn Johnson, a course in phonology, Blackwell, 1999; p. 621
... Bunche[?], diplomat, winner of the Nobel Peace Prize April 16 - Fifi D'Orsay, actress (+ 1983) April 22 - Robert Oppenheimer, physicist (+ 1967) May 6 - Harry ...