Questions & Answers about Mój brat jest w wojsku.
Why is the ending -u in w wojsku instead of -e?
The base word is wojsko (a neuter noun). Normally, neuter nouns ending in -o take the ending -e in the Locative case (like okno becoming w oknie). However, nouns ending in -ko, -go, or -cho take the ending -u instead. This makes it easier to pronounce and avoids awkwardly changing the k sound.
Does wojsko mean 'army' or 'military'?
It can mean both. While Polish has the word armia (which specifically means an army as a land branch), wojsko is the standard, everyday word used to mean the military or the armed forces in general. When someone is actively serving, you always say they are w wojsku.
If I want to say my brother 'joined the army', do I still use w wojsku?
No, because joining implies motion or a change of state. To say he went into the military, you would use the preposition do plus the Genitive case: Mój brat poszedł do wojska (My brother went to the army). You only use w wojsku (Locative case) to describe his current, static situation.