Свой is a reflexive possessive pronoun that translates to “one’s own.” It always refers back to the subject of a verb. Therefore, in a sentence like Я люблю свою жену “I love my wife”, it translates to “my”, however, in a sentence like Он говорит о своей работе “He’s talking about his (own) job”, it translates to “his.” As you can see in both of these examples, свой refers back to the subject.
You may be wondering “Just why in the heck is свой around when we have мой, твой, его, её, наш, ваш, and их?” Well, always remember that saying “Он любит его жену” is much different from “Он любит свою жену.” In the first example, we are saying literally: He loves his wife. This means that we are referring to him as someone else. However, in the second example, we are saying He loves his own wife, with absolutely no confusion in who is “owning” the wife.
“But is свой required for when talking about things first or second person people own?” Well, it’s not required, but you will find it often! The sentence “Я люблю мою жену” is perfectly fine. Sentences with “ты” as the subject will find свой more often than those with я.
Свой is declined just like мой and твой!
m. masculine; f. feminine; n. neuter; pl. plural; N. Nominative; A. Accusative; A anim. Accusative animate; D. Dative; G. Genitive; I. Instrumental; P. Prepositional
Remember animacy, if you have studied it yet. Animate objects are things that are “living”, while inanimate objects are things that are “not living”. A great example of an animate noun: брат “brother”; A great example of an inanimate noun: дом “home.” Hmmm, I think I’ll write an article about animacy in the future.