The Pronoun.
The Personal Pronouns are, in the nominative: Mi, I; vi, you (sing. and pl.); ni, we; li, he; ŝi, she; ĝi, it; ili, they.
The archaic English thou may be translated by ci.
The Accusative case of the personal pronouns is formed like that of nouns and adjectives, by adding -n. Thus: Min, me; vin, you; nin, us; lin, him; ŝin, her; ĝin, it; ilin, them.
The Reflexive Pronoun of the 3rd person is si (accusative sin), standing for himself, herself, itself, one's-self, or themselves, as the case may be. There is no special reflexive form for the pronouns of the 1st and 2nd person, I, we, and you.
The Indefinite Personal Pronoun is oni (= the French on)—one, people, they, you. Ex.: Li amas sin, he loves himself; ŝi amas sin, she loves herself; ĝi montras sin, it shows itself; ili diras al si, they say to themselves; oni vidas sin, one sees one's-self; mi lavas min, I wash myself; vi laŭdas vin, you praise yourself.
Possessive Adjectives or Pronouns.
By adding the adjectival ending -a to the personal pronouns, the Possessive Adjectives and Pronouns are obtained. Thus: Mia, my, mine; cia, thy, thine; via, your, yours; nia, our, ours; lia, his; ŝia, her, hers; ĝia, its; sia (reflexive), his, her(s), its, their(s), one's.
Note the following use of sia. In English the sentence, "He saw his friend with his brother," is not clear. Does it mean that he saw his friend (1) with his friend's brother, or (2) with his own brother? In Esperanto, the use of sia makes the meaning quite clear; (1) would be: Li vidis sian amikon kun LIA frato, and (2) would be: Li vidis sian amikon kun SIA frato.
The word mem, meaning -self or -selves, may be added to a personal pronoun to give emphasis. Thus: Konu vin mem, know thyself; li iris mem, he went himself; li mem, himself; li parolis al si mem, he spoke to himself.