Questions & Answers about To jest moja żona. Bardzo ją kocham.
Why do we use ją here instead of ona?
ona is the subject form, meaning "she". In the second sentence, the wife is the object of the action—she is the one being loved. The verb kochać (to love) requires the accusative case for its object, and the accusative form of ona is ją (her).
Why is ją placed in the middle of the sentence instead of at the end?
Short pronouns like ją are called "clitics". They are weak words that prefer to lean on stronger words in the sentence. Because of this, they almost always avoid being placed at the very end of a sentence. Tucking ją right before the verb (Bardzo ją kocham) sounds much more natural than putting it at the end (Bardzo kocham ją).
Where is the word for "I" in "I love her very much"?
In Polish, the verb ending usually tells you exactly who is doing the action. The -am ending in kocham already means "I love". Adding the pronoun ja (I) isn't necessary and would actually sound unnatural here, as if you were heavily emphasizing "I love her (even if someone else doesn't)."
Why doesn't moja żona change its form like ją does?