Pinyin, or Hànyǔ Pīnyīn, is the official romanization system for Standard Chinese in mainland China, Malaysia, Singapore, and Taiwan. It is often used to teach Standard Chinese, which is normally written using Chinese characters. The system includes four diacritics denoting tones. Pinyin without tone marks is used to spell Chinese names and words in languages written with the Latin alphabet, and also in certain computer input methods to enter Chinese characters. The pinyin system was developed in the 1950s by many linguists, including Zhou Youguang, based on earlier forms of romanization of Chinese. It was published by the Chinese government in 1958 and revised several times. The International Organization for Standardization (ISO) adopted pinyin as an international standard in 1982, followed by the United Nations in 1986. The system was adopted as the official standard in Taiwan in 2009, where it is used for romanization alone (in part to make areas more English-friendly) rather than for educational and computer-input purposes.