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
... Acromesomelic dysplasia[?] Acromicric dysplasia[?] Acroosteolysis dominant type[?] Acroosteolysis neurogenic[?] Acroosteolysis osteoporosis skull and mandible ...