Whose book? To whom?
Distinguish ownership, a recipient, and an inanimate object.
Possessive words
իմ my; քո your (familiar singular); նրա his/her; մեր our; ձեր your (plural/polite); նրանց their. These go before the noun: իմ գիրքը = my book. Before է, use գիրքն: Սա իմ գիրքն է։
Owner versus recipient
ուսանող = student; ուսանողի գիրքը = the student’s book (genitive owner); ուսանողին = to the student (definite dative). Նամակ means a letter and can remain bare as an indefinite inanimate object.
Ես ուսանողին նամակ եմ գրում։
I am writing a letter to the student.
Learn forms with their roles
հայր father → հոր in հոր գիրքը (father’s book). Noun stems can change. Nominative identifies a subject; accusative marks a direct object. With an inanimate object like գիրքը, these forms coincide. Specific human direct objects often take the dative-shaped form instead; do not generalize from books to people.