alt Hacker NewsIt was very surprising for me when I visited the US to see just how much space was wasted writing everything out on every sign and sometimes in giant words on the road.
It did also make me a bit worried about the expected level of driver education...
To me it's odd to imply people must be stupid because they're expected to read a few simple words such as "Left lane must turn left" rather than to memorize a bunch of symbols.
American signs very frequently combine both styles - for instance, you see the above words next to a sign with arrows for whatever lanes, wordlessly illustrating the turn types permitted.
If someone is a new driver, who hasn't seen the symbolic signs enough, the word signs are a good fallback. The goal is to maximize accessibility.