Qu'est-ce que vs. que vs. quoi

Understanding the use of 'qu'est-ce que', 'que', and 'quoi' in French is crucial for mastering question formation. Each term plays a specific role in the construction of different types of questions.

Qu'est-ce que

'Qu'est-ce que' is used at the beginning of a sentence to ask 'what' about an object or an action. It literally translates to 'what is it that'.
Qu'est-ce que tu fais ?
(What are you doing?)
Qu'est-ce que c'est ?
(What is it?)

Que

'Que' is a more formal or literary way of asking 'what', typically used at the beginning of a question, and requires reversing the subject and verb.
Que fais-tu ?
(What are you doing?)
Que veut-elle dire ?
(What does she mean?)

Quoi

'Quoi' is used at the end of sentences in informal contexts or with prepositions. It asks for specific information about an object or situation.
Tu fais quoi ?
(What are you doing?)
De quoi parles-tu ?
(What are you talking about?)

Summary

'Qu'est-ce que', 'que' and 'quoi' all translate as 'what', but are used in different contexts in French. 'Qu'est-ce que' introduces detailed inquiries, 'que' is formal and requires inversion, while 'quoi' fits informal conversation and certain structures with prepositions.