Questions & Answers about Я вижу твои глаза.
The verb for "to see" is видеть. Why does it change to вижу with a ж?
Many Russian verbs that have a stem ending in д change it to a ж just in the "I" form. So видеть becomes я вижу (I see). For the other forms, the regular consonant comes back, as in ты видишь (you see).
The word for "eye" is глаз (masculine). Why does it end in -а here?
глаз has an irregular plural! Instead of taking the regular -ы ending for masculine words, it takes a stressed -а to become глаза (eyes). You will see this irregular stressed -а plural on a few other common masculine nouns, such as дом (house) becoming дома.
Why do we use твои instead of твой?
твои is the plural form of "your". Because глаза (eyes) is plural, the possessive word has to match it in number.
"Your eyes" is the direct object being seen. Why doesn't твои глаза change to the Accusative case endings?
It actually is in the Accusative case! However, for inanimate nouns (things that aren't people or animals) in the plural, the Accusative case looks exactly identical to the Nominative (dictionary) form. Because eyes aren't whole living beings, твои глаза doesn't change its spelling.