heyoudaoicibaDictYouDict[he 词源字典]
he: [OE] He comes ultimately from a prehistoric Indo-European base *ki-, *ko-, which denoted in general terms ‘this, here’ (as opposed to ‘that, there’) and occurs in a number of modern English demonstrative pronouns and adverbs, such as here and hence. The most direct use of the demonstrative is for the ‘person or thing referred to’, and so *ki- has come down directly via Germanic *khi- as the third person singular pronoun he (of which him, his, she, her, and it are all derivatives).
=> him, his, it, she[he etymology, he origin, 英语词源]
he (pron.)youdaoicibaDictYouDict
Old English he, pronoun of the third person (see paradigm of Old English third person pronoun below), from Proto-Germanic *hi- (cognates: Old Saxon, Old Frisian, Middle Dutch he, hi, Dutch hy, Old High German he), from PIE *ki-, variant of *ko-, the "this, here" (as opposed to "that, there") root (cognates: Hittite ki "this," Greek ekeinos "that person," Old Church Slavonic si, Lithuanian šis "this"), 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).

case SINGULAR - - PLURAL
- masc. neut. fem. (all genders)
nom. he hit heo, hio hie, hi
acc. hine hit hie, hi hie, hi
gen. his his hire hira, heora
dat. him him hire him, heom

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.