mine is mainly because i adore the Japanese culture and technology and you can always get the most recent infomation from a Japanese site.
plus the thrill of understanding the meaning of Japanese songs truly by knowing what they are singing about make the song more beautiful.
plus all Japanese girls are ... Nihon-no minasan wa hawai desu.

When you typed "hawai desu" I assume you meant to say "kawaii desu." Hawai is a place (Hawaii), and Kawaii is roughly "cute."

I study Japanese because it's what I do; I love it, it's one of my passions (not the only one), and it's very rewarding. A lot of "fun" cultural aspects to Japan, including anime, manga, Karaoke, music, movies, video games, and the like. Also, I like the challenge of a language radically different from my own.

Just because.

Nihon no minasan wa hawai desu = Japan's everyone is Hawaii.
Japanese girls are cute = Nihonjin no joshi wa kawaii desu.

i was forced to learn because my mother is japanese. it sucked to go to japanese school on saturdays when all your classmates are at home watching cartoons. ^_^

the japanese population is declining as well as their economy so it might not be the best to learn in terms of economics. however, they're still a strong country so it couldn't hurt. as world populations go and how many speak it, again not a wise choice to learn japanese as you can only use it in japan. but if something interests you, it shouldn't matter why you learn, just learn.

Well, my first reason was that I wanted to understand my favorite shows in their original language. But soon after I got started I realized how interesting and beautiful the language is. Plus, I get a thrill every time I can understand something in Japanese. It also makes me feel smart and it has improved my memory by a noticeable amount. The last reason is that I want to be a linguist in the Air Force when I get older and so I want to know lots of languages.

So, I have a lot of reasons for why I'm studying it.

My nationality is Japan.

One reason I wanna learn it is most of the songs I sing are in Japanese, i learned the words in Romaji on Animelyrics.com

The other reason is because I love anime and I wanna be able to understand Naruto Shippuden!

i'm a buisness major in school so japan has a good economy and japanese would be a good thing to know... i love the language! it's hard though!