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
... bladder to the outside of the body. The urethra has an excretory function in both sexes, to pass urine to the outside, and also a reproductive function in the male, as a ...