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
... himself mainly to the doctrines of Hegel and Schleiermacher. After holding the chair of philosophy at Halle for two years, he became, in 1833, professor at the university ...