"What are you saying?"
Translation:Qu'est-ce que tu dis ?
There are 3 ways of asking this question in French:
- formal with a Verb-Subject pronoun inversion: que dis-tu ? / que dites-vous ?
- standard with "est-ce que" + a statement form: qu'est-ce que tu dis ? / qu'est-ce que vous dites ?
- informal/in speech, as a statement: tu dis quoi ? / vous dites quoi ?
"Dis-tu" has "tu" as the subject of "dis", and this is a formal question.
"Tais-toi" has "toi" as the direct object of "tais" and this is a command in imperative.
The reason for this is that if it were not a question or a command, you would have:
- Tu dis = you are saying
- Tu te tais: reflexive verb = you keep quiet
In the imperative, the subject disappears:
- Dis ! = Say!
- Tais-toi ! = Keep quiet!
In the interrogative, the subject is inverted with the verb:
- Dis-tu ? = Are you saying?
- Te tais-tu ? = Do you keep quiet?
If you are referring to n6zs' comment “use (qu')est-ce que before (not for!) a statement,” he meant to say: Don't use inversion after (and in addition to) “(qu')est-ce que.” Rather, use the indicative form that is used to form statements.
- Statement: tu viens (you are coming)
- Question: Est-ce que tu viens? (are you coming?)
- but not: Est-ce que viens-tu – wrong.
- Question by inversion: Viens-tu? (are you coming?)