ShuangPin (also known as ShuangDa) is an input method based on Pinyin input method, which can be regarded as a kind of improvement of QuanPin. It greatly improves the input speed of Pinyin input method by mapping each consonant or vowel containing multiple letters of Hanyu Pinyin to a certain key, so that each sound can be typed with up to two keystrokes. This kind of correspondence between consonants and keys is often called a ShuangPin scheme. This scheme is not fixed, and most popular Pinyin input methods nowadays support ShuangPin with their own schemes and allow users to customize their schemes. Common programs include Xiaohe ShuangPin, Microsoft Pinyin 2003, Smartabc, Pinyin Jaga, Ziguang ShuangPin, Sogou ShuangPin, Natural Code and so on. The main difference between these programs is the key arrangement of rhyming letters.

Full Spelling, as the name suggests, is complete spelling