Somewhat purposefully, I am taking Japanese now so as to get accustomed to thinking/living/learning Chinese and Japanese concurrently. I realize that trying to tackle both at once may be seen as a potential hindrance, but I believe there may be benefits. I have already experienced learning two languages at once, French and Spanish. By studying them at the same time, I had to adapt to keeping them separated both in and out of class. This is excellent practice for those real world situations where one is forced to switch between languages. For example, I was in Tokyo for just one day a few weeks ago. While there I spoke both French and Spanish with people as well as English and my rudimentary Japanese. Well, actually I spoke some Chinese to them too, but not on purpose! It was both fun to communicate in multiple languages as well as practical. Though my native English is currently the lingua franca of the world, not everyone learns English and not everyone chooses to pursue English as their best foreign language.
Another point I'd like to mention is that I am interested in the relationship between kanji and hanzi (written 漢字 or 汉字 depending on where you are from), and how the characters will play into my learning Japanese. I have reached the point of Chinese character recognition where I can "understand" many of them in a reference book for English-speaking students of Japanese kanji. But (and this is a big caveat) I read the characters as though they were Chinese! So when I encounter Japanese sentences with kanji my natural instinct is to insert Chinese in the middle of a Japanese phrase. Even though the way I approach kanji will undoubtedly be influenced by my study of Mandarin, I don't think it will completely replicate the way that a native Chinese speaker would be. It is nice, however, having already adapted to the idea and practice of recognizing unique characters which are not Roman letters. I am not particularly looking forward to writing out more kanji handwriting practice (not my favorite, done it in previous Japanese and Chinese classes). This is not to say I have great handwriting! Sore writing hand aside, I find the history of languages and linguistics quite intriguing (I've also studied some Historical and Anthropological Linguistics). I hope to have a few interesting discussions about these sorts ideas with other students who confront active engagement with English, Japanese, and Chinese (regardless of their backgrounds). I am also interested in the pedagogical methods in teaching kanji (as well as the overarching approach to teaching Japanese at Columbia), will they (it) be different than my previous experience?
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There are other reasons for me to learn Japanese as well--academically, professionally, and personally, yet I would like to save some of them for another post. Until then!