[KyleGoetz]

Korean and Japanese are very similar. When I lived in Japan, some of my (native Japanese) friends told me tales of walking somewhere in Japan, hearing someone going off in Korean, and thinking it was Japanese until they realized they didn't understand anything the person was saying.

The grammar is very similar (sometimes I even hear things and recognize the patterns if not the meanings--the famous example is "nida" in Korean, which is like "desu" in Japanese, the copula). Additionally, the lilt (??) of the language is quite similar. Being a Japanese speaker who attends a university with a lot of exchange students and grad students from Korea, I've always thought that Korean sounds an awful lot like a Japanese person with a local anesthetic deadening their cheeks and tongue a bit to cause a shift in pronunciation.

In any case, the speech pattern of pitch rather than volume/stress as the primary I-don't-know-the-linguistic-term is native to both Korean and Japanese.

If someone says Chinese is more similar to Japanese than Korean is, they likely know only one of the three languages and have no familiarity with the other two. I've studied Japanese and Chinese, and, aside from a handful of kanji (recall that their writings systems have dramatically diverged since the simplified writing system of China and the post-WWII (I think this was when the change happened) writing reform in Japan), they are extremely dissimilar.