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
... density of 173.1/km² (447.3/mi²). The racial makeup of the town is 89.99% White, 4.23% African American, 0.97% Native American, 0.97% Asian, 0.00% Pacific ...