In French, the general form of the possessive adjectives is determined by the grammatical gender and number of the possessor, and the ending is determined by the possessed.
This differs from English where the person of the general form of the possessive adjective is determined by the sexual gender and grammatical number of the possessed only.
• mon/ma/mes = my (first person singular possessor)
mon = singular masculine possessed
mon = singular feminine possessed, the next word starts with a vowel
ma = singular feminine possessed, the next word starts with a consonant
mes = plural possessed
• ton/ta/tes = your (second person singular possessor)
ton = singular masculine possessed
ton = singular feminine possessed, the next word starts with a vowel
ta = singular feminine possessed, the next word starts with a consonant
tes = plural possessed
• son/sa/ses = his/her/its/one's (third person singular possessor)
son = singular masculine possessed
son = singular feminine possessed, the next word starts with a vowel
sa = singular feminine possessed, the next word starts with a consonant
ses = plural possessed
Note : English matches the adjective with the sexual gender of the possessor, that's to say male, female or no sex. French matches the adjective with the grammatical gender of the possessed, that's to say masculine or feminine.
So do not make the mistake of believing that "son" necessarily means "his". It can also mean "her" or "its". Same thing for "sa" and "ses".
• notre/nos = our (first person plural possessor)
notre = singular possessed
nos = plural possessed
• votre/vos = your (second person plural possessor)
votre = singular possessed
vos = plural possessed
Note : the second person plural is used for the actual plural, that's to say when there are several persons, but it can also be used as a polite form even when there's only one person.
• leur/leurs = their (third person plural possessor)
leur = singular possessed
leurs = plural possessed
