Keyboard input methods can be classified in three main types:
The following are just some samples of Chinese input methods. Many of those input methods have variations. Full Pinyin and Double Pinyin are variations of the pinyin input method. In addition, the methods which require the user to select a character from a menu generally have sophisticated methods for guessing which characters the user intends based on context.
Each standard has its strengths and weaknesses and usage varies between people. For example, for someone who is already familiar with pinyin, the pinyin method can be learned instantly, and most Mandarin speakers master pronunciation through pinyin. However, the maximum typing rate is limited, and learning the system can be difficult for those not familiar with pinyin. Wubi takes much effort to learn, but expert typists can enter text much faster with it than with the phonetic methods. Because of these factors, there is very little likelihood of a "standard" method evolving.
Other means of entering Chinese characters include handwriting recognition, OCR and voice recognition. The first and last of these usually must be “trained” before use; that is, the user must first use the system in a special “learning mode” so that the system can get accustomed to the user’s handwriting or speech pattern, and failure to do so will increase the recognition error rate. These, especially the latter two, are less frequently used than keyboard-based input methods and, as with even the most advanced English language systems, suffer from relatively high error rates, especially when used without proper “training”, though the error rates are an acceptable trade-off to many users.
Particular mention should be given to handwriting recognition systems: although mostly associated with stylus and tablet-based systems, it is in fact one of the built-in input methods in Windows XP systems. Handwriting recognition systems for Chinese are generally far more reliable.
Finally, some systems allow Chinese characters to be entered by typing their equivalent English words.