Cavesa wrote:You simply get a much bigger pool to choose what you want from. That's what knowing a language is meant to give you. You may not notice that, as you've got the privilege of being an English native, the whole planet caters to you. But for some of us, using resources based in our native languages simply means settling for much less and getting much worse education as a result.
While it's true that resources in English are generally very good or otherwise the best there are (even if they aren't great), there are languages here and there for which it's much better if you use non-English resources.
For example, while in theory you can learn Classical Chinese with existing English resources only, there would be a ton of great stuff in Mandarin that you'd be missing out on. The best English grammar (Edwin Pulleyblank's) and dictionaries (John Cikoski's, Paul Kroll's) don't really compare to the best grammars (Hé Lèshì & Yáng Bójùn's, Guō Xīliáng's, Yì Mèngchún's) and dictionaries (Gǔdài Hànyǔ Cídiǎn, Hànyǔ Dà Cídiǎn) available in Mandarin. I have similarly come across conlangers interested in South American languages groaning at having to learn Spanish or Portuguese to make use of Guarani/Mapudungun/Old Tupi/etc. resources, since even when linguists are native English speakers, they tend to publish most things in Spanish/Portuguese.
Then there's also the thing of other languages having great resources, even if those in English are also pretty great.
For example, the best dictionary of Latin synonyms, explaining the difference between them, is in German (Ludwig Döderlein's unabridged dictionary, in six volumes, plus a seventh appendix volume). Assimil produces lots of wonderful little textbooks in French (as we all know), often without an English equivalent, as it is the case with Romanian and Latin (I've heard of a guy from northern England that teaches Latin for cheap who uses Le latin sans peine while ignoring the French text!). Some people who study Latin swear by the Italian version of Athenaze as the best 1st or 2nd textbook to use when learning Ancient Greek because most of it is an easy reader (better than the English original, they say). I've heard of people who have benefitted from looking up words in the Katharevousa Greek version of the Greek-English Liddell-Scott-Jones dictionary (a.k.a. the "Big Liddell" or the "Great Scott"), because it wasn't just a translation but also an expansion, including many words that are missing in the old dictionary (even in its 1940 edition with the 1996 Supplement).