So? Reading isn't even a part of knowing a language. Vocabulary is the part of learning a language that causes by far the least problems. Knowing that δένδρον means "tree" is easy, but it won't help you use it in a sentence. That problem doesn't go away if the word that means "tree" is 木 instead.
Here's the opening of a Latin poem:
Quis multa gracilis te puer in rosa
perfusus liquidis urget odoribus
grato Pyrrha sub antro?
Here's what it looks like if you have perfect knowledge of the vocabulary involved:
What many slender you boy in rose
soak liquid press odor
pleasant Pyrrha[a name] under cave?
Does that help you to read it? (Bear in mind that Latin and English are, unlike Chinese and Japanese, related to each other. You even got three words that are more or less identical in Latin and English! [In all three cases, as in the case of Sino-Japanese vocabulary, that's due to borrowing rather than a relationship between the languages. But you can also see a true cognate - Latin quis is in a real sense the same word as English what.])
You are very wrong, and I know not only because I learned some Japanese (C1 level) and some Chinese (A2), and experimented first hand how easy and helpful it's to transfer vocabulary, but also because I read a lot of the scientific literature on this exact subject. Japanese has 60-70% compound words using morphemes of Chinese origin, and about 60% percent have the same exact meaning in this two languages[1].
Learning vocabulary is also not "the easiest" part of learning a language either, it's one of the most fundamental step of learning a language, which take a massive amount of time. If time can be shelved here (and indeed is in-between Japanese-Chinese, Japanese-Korean, etc. even Vietnamese to Japanese) it can be reinvested elsewhere. Heck, I've seen a Taiwanese girl getting her JLPT N3 after one semester of Japanese study just thanks to the shared vocabulary and characters.
So, for context, I wrote the comment you replied to as a French who speaks Japanese fluently and has been learning both Cantonese and Mandarin. So I am talking from experience and I completely disagree with you.
First, I disagree that vocabulary is the part that causes by far the least problems, instead in general my approach to learning any language is to first focus on learning the vocabulary. And to counter your latin example, when I was a child, I studied Latin, after my first 6 months of latin, I went to live in Spain for 5 months, when I came back latin was significantly easier than it was before. I could understand a lot more than I could before. The only reason for this was that I know could speak Spanish and could use that to guess words.
Of course this works a lot better on writings that are not poems, in general poems like your example are more difficult to understand without knowing the cultural context around them. If you want to really illustrate your point, try with a text that's not a poem and you will see that knowing the vocabulary does indeed significantly help.
Second, reading is absolutely an essential part of knowing a language. At this point, I really don't even know how to answer to this besides asking for clarification why you would come to this conclusion? I'll just say that I would have loved having the significant advantage Chinese students have when it comes to reading Japanese.
Finally, I was going to make the same points historia_novae about how many words really do have the exact same meaning in written form between Japanese and Chinese. But he expressed that better than I could.
> Vocabulary is the part of learning a language that causes by far the least problems.
Strongly disagree. Memorizing vocabulary is a huge barrier to learning a foreign language. You need something like 5000 words just to have basic conversational competency, and far more to understand texts about a domain, or slang, or literature.
Nice example, but quis is cognate with who. I'm guessing quod is the closer cognate of what, though quid is the better translation in most (or maybe just more canonical) cases.
This is not an easy claim to make; at the level where they coincide, it's hard to distinguish the words. In the same sense that quis and who are identical with each other, who and what are also identical with each other.
Compare wiktionary's entries on the etymology of who and what:
> [who: ] From Middle English who, hwo, huo, wha, hwoa, hwa, from Old English hwā [], from Proto-West Germanic *hwaʀ, from Proto-Germanic *hwaz, from Proto-Indo-European *kʷos, *kʷis.
> [what: ] From Middle English what, from Old English hwæt (“what”), from Proto-Germanic *hwat (“what”), from Proto-Indo-European *kʷód (“what”), neuter form of *kʷós (“who”)
Wiktionary does elaborate, on the page for kʷís, that Indo-European proper had two unrelated stems *kʷi- [giving us interrogative pronouns] and *kʷo- [giving us relative pronouns], but that these tended to be combined in later languages. If you want to distinguish them, you can say that quis is not cognate with what. But you couldn't then go on to say that it is cognate with who; both who and what would be cognate with quod.
Here's the opening of a Latin poem:
Here's what it looks like if you have perfect knowledge of the vocabulary involved: Does that help you to read it? (Bear in mind that Latin and English are, unlike Chinese and Japanese, related to each other. You even got three words that are more or less identical in Latin and English! [In all three cases, as in the case of Sino-Japanese vocabulary, that's due to borrowing rather than a relationship between the languages. But you can also see a true cognate - Latin quis is in a real sense the same word as English what.])