Could somebody explain to me in words of one syllable the difference between a switch, a hub, and a router?
No. I mean, router has two, right there. But if you'll allow a couple more, here goes:
They are, in order of increasing complexity hub -> switch -> router.
A hub doesn't do much. It's like a splitter. Whatever comes in one pipe, goes out all the other. A switch is a little more complex. It knows enough to only send stuff down my wire that's supposed to get to me. It makes it more like I'm getting the full pipe -- I am, but not all the time. With a hub, everyone's data is in the pipe all the time. With the switch, sometimes it's all mine, sometimes I have no access at all.
A router is a switch that sits at the junction of two networks. So traffic in network A stays on the A side, unless it's specifically intended for network B, or vice versa. The device connected to my cable modem is a router, for those reasons.
Or those used to be the definitions. In today's world of convergence, I think hub is becoming an umbrella term, perhaps because so few of the bare bones hubs are used, compared to five or ten years ago.