[KyleGoetz]

Originally Posted by sakaeyellow

I speak Cantonese (native), English (native-level), Mandarin and Japanese. As for my Mandarin and Japanese, casual conversation is okay. But I will surrender if I am to speak these two languages in a debate or to persuade an uninterested customer to buy. And I have difficulty understanding non-Tokyo accent.

Let me suggest the definition of "I can speak xxxx language":
When you encounter a new German word, you ask a native German speaker in German what the word means. The native speaker answers in German. You understand it fully and thus learn that word. If you can do all these, you can speak German, because you have the ability to build your German vocabulary with German input only.

Let me tell you more about Kanji.
The Japanese imported Kanji from China more than 1000 years ago. Kanji at that time did not have phrases, because paper was very expensive. Each Kanji had an independent function. Phrases like 進行 and 生命 did not exist. But when the Japanese met the advanced Western culture 100-150 years ago, they used Kanji to translate Western concepts by combining two Kanji into a phrases. Examples are 民＋主＝民主(democracy),科＋学＝科学(science) and 電＋話＝電話(telephone). Phrases like these three had not existed before in Japan or China. And the Japanese invented a LOT of Kanji phrases! The Chinese did not invent their own version but simply imported the Made in Japan Kanji phrases into their daily conversation. Because of export and reimport, modern Chinese vocabulary and Japanese vocabulary in fact share a lot of words. When I say a lot, I mean at least 50%.

For you reference, in the official Chinese name of the People's Republic of China, i.e. 中華人民共和国, 人民(People) and 共和国(Republic) are Made in Japan Kanji phrases.

Thanks for the lesson. I knew some of it already, but that 50%-shared-vocab figure is awesome.