Learn Hardcore Polish: Czy twój telefon działa?

Czy is a yes/no question particle. It doesn’t translate directly into English but signals that the sentence is interrogative. Without Czy, you’d rely on rising intonation alone (e.g. Telefon działa?) to ask “Does the phone work?”

Why is twój used here, and why does it look the way it does?

Twój means “your” (second-person singular). Polish possessive pronouns agree in gender, number, and case with the noun they modify. Since telefon is masculine, singular, and in the nominative case (it’s the subject), the correct form is twój.

Why is telefon in the nominative case?

Because it’s the subject of the sentence. In Polish, subjects take the nominative case. Here telefon (the thing doing the “working”) remains in nominative.

What does działa mean, and which form of the verb is it?

Działa is the third-person singular present tense of działać (“to work” or “to function”). Conjugation in the present tense:

ja działam
ty działasz
on/ona/ono działa

Could I drop Czy and still ask the same question?