Within the context of being unable to read road signs, it's a valid question.
I'll counter Skaw's argument with the inverse: At what point do we have to label everything in multiple languages? Every street sign, warning sign, business description, and so on? How many languages do we need before we stop "discriminating"? I mean, sure, some minorities are more minor than others. That doesn't mean that they forfeit this apparent right to move to a different country without having to learn the language, right?
Slippery slope arguments work both ways, you realize.
There's no reason for any driving test to be written in language more complicated than someone who was making a significant effort to learn the language could understand.
Of course, on the flip side, we have to ask the question: What about those people who are, so to speak, fresh of the boat? Should we then deny them a chance to drive, in a country that is most emphatically not primarily designed around public transit?
It's a reasonably complicated issue, and not one you can resolve with "You're a racist" or "You're an idiot", or "You're a hippy".
These are not the things of which a reasonable debate is made.