Breakdown of Mój brat już nie mieszka za granicą.
Questions & Answers about Mój brat już nie mieszka za granicą.
Because brat is a masculine singular noun and it is the subject of the sentence, so it is in the nominative case.
- mój = my
- brat = brother
The adjective/pronoun mój has to agree with the noun it describes:
- mój brat = my brother
- moja siostra = my sister
- moje dziecko = my child
So mój is simply the correct nominative masculine singular form here.
Polish does not use articles like English a/an and the.
So:
- brat can mean a brother, the brother, or just brother
- mój brat naturally means my brother
The context tells you whether English should use a, the, or nothing.