Look, I apologize if my saying things straight offended some people. I actually used to have a whole long thing saved up to preface any time I ever pointed out that a major Posek was mistaken or didn’t know about something that I would cut-and-paste. But eventually it felt contrived and like I was faking an Anavah that I honestly don’t have. Look, sometimes you have to point things out. Otherwise you can’t learn. The Gemara says this. If you want to be a Talmid Chacham you have to be Kashe K’barzel. It is not ridiculous to say that Rashi didn’t know a language or know about the existence of rice.
HaLeiVi: He quotes individual words. It’s clear, though, that he didn’t understand Arabic or the Spanish Judeo-Arabic. That’s why he has a set of grammatical rules on Chumash that our grammar just doesn’t agree with. He only quotes Shlomo ibn Gabirol because he was the only of the grammarians who wrote in Hebrew. Rashi just didn’t have access to the works in other languages.