Chaozhuyin is a Chinese phonetic symbol input method (Bopomofo IME) that is easy to use with zero learning curve. It is available on the Android platform and supports mobile and tablet devices, including those with a hard keyboard.

To input a Chinese phrase, you only need to input the first phonetic symbol of each word, and you can add any remaining symbols arbitrarily to narrow down the candidates you may want. The program provides several kinds of skins and colors of the soft keyboard, and the keyboard and font size can be adjusted freely.

Chaozhuyin offers great functionality of word or phrase guessing, and the lexicon contains all the cities, streets, and roads names all around Taiwan. It even allows you to import Chinese names in your contacts and output Simplified Chinese.

Additionally, the program features proximity correction, swiping keyboard, English input method, keyboard fan-shaped selector, candidate selection dropdown, and up/down/left/right arrow keys, and voice recognition button. You can also remove your user phrase and backup/restore it by yourself, and move the system phrase database file to and from the SD card.

Note that this is the paid-version of the original Chaozhuyin, and the license is memorized separately from the free download version.