Especially important in places like Europe, where it's common for the driver to be able to read, but unable to speak the language of the country they are currently driving through. I can't speak any Polish, but can travel on Polish roads just fine
1: https://en.wikipedia.org/wiki/Prohibitory_traffic_sign#No_en...
Then there is Hanoi.
Not really. You just need to be able to decipher the sign, which is trivial, even if you can't read it or spell it.