Speed bump signs usually say something descriptive like: SPEED BUMP. Or for those neighborhoods where people need clarification on which direction they need to be traveling to heed the warning, you might get: SPEED BUMP AHEAD. (Not to be confused with SPEED BUMP BEHIND, which would be funny.) However, I've never come across this variety which had text which, up until this point, I thought meant something entirely different:

Speed Hump? HUMP?!!?? What happened to BUMP? A speed hump is not something you drive over, it's something you drive home after an uncomfortable silence. (If you're courteous enough). It's something you do if you're late for work, or on your lunch and pressed for time. You might encounter a speed hump in a broom closet, an airplane bathroom, or when stopped at a long red light and you get bored. BUT FOR THE LOVE OF GOD, IT'S NOT A STREET SIGN!
And why use the word "Speed" in the sign that's trying to get people to slow-the-F down? You get some joker who puts a piece of dried up chewing gum on the sign and half wits all over town mistake it for a comma and read the sign: "SPEED, BUMP" But really who are we kidding? Most don't even look up from their iPods long enough to see those street signs, and when we encounter speed bumps we may go slow over the bump, but then slam the accelerator to the floor to get to the next bump as fast as possible so that our average speed remains the same as if there were no speed bumps.
Speed Hump. Who writes these signs? Probably the same guy who wrote "Brief Case" on that art supply folder. (see archived post "A Briefcase for Morons".