William Page is the young son of George and Margaret Page. Shakespeare isn't at all interested in developing his character but he does devote an entire scene (4.1) to little William getting grilled by his Latin grammar teacher. Poor kid. By the way, this whole episode has absolutely nothing to do with the development of the plot. What's up with that?
Well, we've got a few ideas, Shmoopers. First of all, William's Latin lesson seems like a shout-out to Will Shakespeare's own childhood education, which involved a boatload of Latin, strict teachers, and a brutal schedule. Obviously, our playwright's got a sense of humor about the trauma of learning Latin because William's grammar lesson is chock full of dirty jokes. (Yep. You'll have to read Act 4, scene 1 if you want all the juicy details.)
Okay, fine. But what does any of this have to do with the play? Well, the Latin lesson may not forward the plot but it does give us a sense of what it's like to be middle class and to live in a town like Windsor.
Will's parents are prosperous so, they can afford to send him to school and they obviously think that education is important. (That's why Will's mom makes the kid practice his grammar on what should be his day off.) In a play that is so interested in the day-to-day lives of middle-class folks, the Latin lesson is a perfect snapshot of what it might be like for a kid like William Page to grow up in a small, English town. Check out "Themes: Society and Class" if you want to think about this some more.