Yes/No questions

The most common way to form a yes-no question in informal French is by raising the intonation at the end of the utterance. In writing, you only need to add a question mark: 

Tu prends le bus ou le train?

You’re taking the train?

Vous n’aimez pas voyager?

You don’t like travelling?

Another common way to form a yes-no question is to start the question with the question particle est-ce que. Est-ce que literally means “is it that”. No change in word order is needed:

Est-ce que tu prends le bus ou le train?

Are you taking the bus or the train?

Inversion is the formal way to ask a yes-no question, by inverting the verb and the subject. These are usually linked with a “-” (dash):

Prends-tu le bus ou le train?

Are you taking the bus or the train?

Question words

If a question starts with a question word, the most common word order in French is: question word + est-ce que + subject + verb + (object):

Pourquoi est-ce que tu prends le train?

Why are  you taking the train?

Quand est-ce que le train part?

When is the train leaving?