Formal:
* Parlez-vous anglais? (This is the most common and direct way to ask.)
Informal:
* Tu parles anglais? (This is more casual and you would use it with someone you know well.)
You could also ask:
* Est-ce que vous parlez anglais? (This is slightly less direct than "Parlez-vous anglais?")
* Vous parlez anglais? (This is a shorter way to ask and is appropriate for most situations.)
It's important to note that the French language often uses the formal "vous" even when addressing someone you know well, especially if they are older or in a position of authority.