s after vȯiceless consonant sounds other than s, sh, ch; z after vowel sounds or vȯiced consonant sounds other than z, zh, j; ə̇z after s, sh, ch, z, zh, j noun suffix or pronoun suffix
Etymology: Middle English -s, -es, gen. singular ending of nouns, from Old English -es, gen. singular ending of some masculine & neuter nouns; akin to Old High German -es, gen. singular ending of some masculine & neuter nouns, Old Norse -s, Gothic -is, Greek -ou, Greek (Homeric) -oo, -oio, Sanskrit -asya
— used to form the possessive of singular nouns
boy' s
of plural nouns not ending in s
children' s
of some pronouns
anyone' s
and of word groups functioning as nouns
the man in the corner' s hat
or pronouns
someone else' s