inherent multiplicity

Excuse me while I step into a useless linguistics-ish rant with no relevance to anyone beyond myself and the tiny corner of my brain I am currently occupying. I am thinking about the multiplicity inherent in related language groups. As I mentioned before in this blog, I am studying Chinese at work. A coworker (who assumed I study Japanese and knows I also study Korean, among others) recently told me that he thought I was damaging my linguistic progress by learning Chinese. I waxed on philosophically that learning multiple languages in related families actually reinforces the others because of inherent cross-overs. Beyond that, I assured him, the study of several language-systems was bound to do me brain a world of good--- mental exercise to the extreme, so to speak. A Japanese friend of mine recently wrote a book about studying Korean. I bought it today, and was flipping through it's pages casually when the word "umbrella" hit me as a perfect example. (Hope you have Asian fonts installed for this.) In Korean it is 우산 [usan] and in Chinese it is 雨伞 [yǔsǎn]　and in Japanese 傘 [kasa]. Korean although wrote in a different written system is startlingly close to the Chinese (which, in the quoted example, utilizes simplified characters. Traditional ones are the same as the Japanese character) and the Japanese is pronounced different but uses the same characters (although usually Japanese people just use the second character of the two, although the first can be read as "rain" in Japanese, rendering it easily understood as "rain Umbrella"). Thus knowledge of any of the three language systems supports acquisition of the other two. Now it's not usually as clean cut as this perfect example, there are endless words that don't correlate, but the fact that any of them do brings these languages into a sort of "family" so to speak. Fascinating, for me anyway.