In spoken French, the most frequently used question word is arguably quoi—especially in informal contexts. You'll often hear phrases like Tu fais quoi ?, Il dit quoi ?, or C’est quoi ça ?. It’s quick, direct, and suits casual conversation. However, in more formal or written contexts, qu’est-ce que or que would be preferred.

Other common question words in French used frequently in speech include où and comment, particularly in everyday scenarios. For example, Comment tu t’appelles ? and Où tu vas ? are phrases often used when meeting people or making plans. While all question words are useful, understanding which ones dominate in casual vs formal situations helps learners adapt their language accordingly.