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
... of which 37.3% have children under the age of 18 living with them, 60.9% are married couples living together, 12.2% have a female householder with no husband present, and ...