Pinyin, more formally called Hanyu Pinyin, is the most common Standard Mandarin romanization system in use. Hanyu means the Chinese language, pin means "spell" and yin means "sound". It is also known as a scheme of the Chinese phonetic alphabet.
Pinyin uses the Latin alphabet to represent sounds in Standard Mandarin. The way these letters represent sounds in Standard Mandarin differs from other languages that use the Roman alphabet. For example, the sounds indicated in pinyin by "b" and "g" correspond more closely to the sounds indicated by "p" and "k" in some Western uses of the Latin script, e.g., French. Other letters, like "j", "q", "x" or "zh", indicate sounds that do not correspond to any exact sound in English. Some of the transcriptions in pinyin, such as the "ang" ending, do not correspond to English pronunciations either. This means that people who have not studied Chinese or the pinyin system are likely to severely mispronounce some words if they attempt to pronounce pinyin according to their own language spellings.
Hanyu Pinyin was approved in 1958 and adopted in 1979 by the government in the People's Republic of China. It superseded older romanization systems such as Wade-Giles (1859; modified in 1892) and Chinese Postal Map Romanization, and replaced Zhuyin as the method of Chinese phonetic instruction in mainland China. Hanyu Pinyin was adopted in 1979 by the International Organization for Standardization (ISO) as the standard romanization for modern Chinese. It has also been accepted by the Government of Singapore, the Library of Congress, the American Library Association, and many other international institutions. It has also become a useful tool for entering Chinese language text into computers.
The primary purpose of pinyin in Chinese schools is to teach Standard Mandarin pronunciation. For those Chinese people who speak Standard Mandarin at home, pinyin is used to help children associate characters with spoken words which they already know; however, for the many Chinese people who do not use Standard Mandarin at home, pinyin is used to teach them the Standard Mandarin pronunciation of words when they learn them in elementary school.