Origin and history of her

Old English he, pronoun of the third person (see paradigm of Old English third person pronoun below), from Proto-Germanic *hi- (source also of Old Saxon, Old Frisian, Middle Dutch he, hi, Dutch hy, Old High German he), from PIE *ki-, variant of root *ko-, the "this, here" (as opposed to "that, there") root, and thus the source of the third person pronouns in Old English. The feminine, hio, was replaced in early Middle English by forms from other stems (see she), while the h- wore off Old English neuter hit to make modern it. The Proto-Germanic root also is the source of the first element in German heute "today," literally "the day" (compare Old English heodæg).

The paradigm in Old English was: MASCULINE SINGULAR: he (nominative), hine (accusative), his (genitive), him (dative); FEMININE SINGULAR: heo, hio (nom.), hie, hi (acc.), hire (gen. and dat.); NEUTER SINGULAR: hit (nom. and acc.), his (gen.), him (dat.); PLURAL: (all genders) hie, hi (nom. and acc.), hira, heora (gen.), him, heom (dat.).

Pleonastic use with the noun ("Mistah Kurtz, he dead") is attested from late Old English. With animal words, meaning "male" (he-goat, etc.) from c. 1300.

c. 1300, hires, from her; thus a double possessive. Possessive pronouns in Modern English consist of the predicative (mine, thine, his, ours, yours, theirs) that come after the subject, and the attributive (my, thy, his, her, our, your, their) that come before it. In Old English and early Middle English, they were identical. To keep speech fluid, speakers began to affix an -n to the end of predicative my and thy before words that began with vowels. This began late 13c. in the north of England, and by 1500 was standard.

Then the predicative and attributive pronouns split, and the remaining pronouns in that class took up -s, the regular affix of possession. But the non-standard speech of the Midlands and south of England extended -n throughout (hisn, hern, yourn), a habit attested from 14c. and more regular than the standard speech, which mixes -s and -n.