why in "Parlez-vous français ?" in parlez before vous?
This is basically a very simple example if an "Inversion", a formal French method to ask questions. You will learn more about it in the "Questions" skill in your French tree. (Basically you just put the verb before the subject in a statement and form a question). You can observe this in English too: Statement: He is there. Question: Is he there? Same thing in French, just that there is a hyphen in between the flipped words.