pinyin

Pinyin uses Roman letters to represent sounds in Standard Mandarin. The way these letters represent sounds in Standard Mandarin differ 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.
By letting Roman characters refer to specific Chinese sounds, pinyin produces a compact and accurate romanization, which is convenient for native Chinese speakers and scholars. However, it also means that a person who has not studied Chinese or the pinyin system is likely to severely mispronounce words, which is a less serious problem with some earlier romanization systems such as Wade-Giles.