Why does Vivi/Fat Dragon always chat in CAPS?

When using a computer in Chinese, you type the Chinese phonetically and the computer replaces it with characters. This system is called pinyin. If you want to type roman letters instead. You can type caps and the computer will not replace them.

example; i type 'wo meiyou zhu' with chinese keyboard = 我没有猪， or i type WO MEIYOU ZHU = WO MEIYOU ZHU.

You can also change keyboard language on your computer, but I assume Vivi usually does not do that and just uses caps instead.