Originally Posted by tiecollector
Japanese and Korean share similar grammar and both are derived from Chinese words. They also share some of the same words. A Korean can go to Japan and become fluent pretty quickly, and vice versa. NR would be a better judge of this but this is what I have heard from Koreans and I associate with many.
My Korean friends all speak Japanese better after a few years than I do after twenty, so yes, the grammar is very close. The rhythms and cadences are as well. When I hear Korean spoken, my brain always tries to process it as Japanese even though I can't understand a word. It's similar to what people have said about Portuguese and Russian.
It's not really accurate to say that either language was derived from Chinese. Rather, they took the Chinese writing system and adapted it to their own languages. I can't speak for Korean, but in the case of Japanese, adoption of the Chinese characters enriched the language a great deal, as new vocabulary and concepts were added to an existing native language that lacked a writing system. Perhaps in that sense, a significant portion of the language was derived from Chinese. However, by the same token, Japanese is now appropriating an increasing number of words from English, but you could hardly say it is derived from English.
The meanings and combinations of Chinese characters used in Japanese are quite different from the meanings and combinations used in Chinese, and the pronunciations of the two languages don't resemble one another in the least. So, the extent of any similarity are shared elements in the writing system.