Seeing all those recent posts by CliffordK and rumrunn6, I'm surprised by the amount of written warnings and instructions, and more so the expectation for drivers to read and comprehend them while passing by at speed.
Around here the vast majority of signs use sign language because it's quicker to recognize as long as you know the accompanying rules. If there's a sign indicating a pedestrian zone, cyclists are expected to know the traffic law saying that they have to get off their bikes, and if there's a small bicycle sign underneath they're expected to know that cycling is permitted at a cautious pace while paying attention to pedestrians. And "ZONE" or "frei" (free as in permitted) is already a lot of words, most signs have none at all.