Written Japanese is an interesting concept. With the Roman alphabet you can relatively easily figure out the pronunciation of a word even if it is completely new to you (silent letters excepted). With Japanese, you either know it or you don't. There is no middle ground. And it takes until adulthood to learn the approximately two thousand standard charters used by newspapers and government circulars. But once you learn them it is quick and as each character is essentially a word, it's outstandingly effective for Twitter.
There is a catch though. I once asked two Japanese friends to read out loud an article from The Yomiuri, Japan's most popular daily newspaper (see "Ten Things to do in Tokyo"). Quickly the exercise became something of a discussion as they disagreed and corrected each other on the pronunciation. The issue being that kanji characters have at least two pronunciations and often many more. The correct sound is defined by the positioning and conjugation of the character rather than the character itself. This leads to the interesting situation that a Japanese person will be able to understand a newspaper but not necessarily be able to read it out loud.
And here's the challenge. Take a very simple character for the Japanese word for "person" hito 人. The pronunciations can range from hito, bito, to nin, jin etc and keep going. Like naming the Seven Dwarves, it's a great pub game trying to remember all the different ways to pronounce a single ideogram. And in this case, I believe there's seven. But then again, I could be wrong.