(IPA), an alphabet developed with the intention of enabling students and linguists to learn and record the pronunciation of languages accurately, thereby avoiding the confusion of inconsistent, conventional spellings and a multitude of individual transcription systems. One aim of the IPA was to provide a unique symbol for each distinctive sound in a language—that is, every sound, or phoneme, that serves to distinguish one word from another.

IPA primarily uses Roman characters; other letters are borrowed from different scripts (e.g., Greek) and are modified to conform to Roman style. Diacritics are used for fine distinctions in sounds and to show nasalization of vowels, length, stress, and tones. The concept of IPA was first broached by Otto Jespersen (Jespersen, Otto) in a letter to Paul Passy of the International Phonetic Association and was developed by A.J. Ellis, Henry Sweet, Daniel Jones, and Passy in the late 19th century.

The IPA can be used for broad and narrow transcription. For example, in English, there is only one t sound distinguished by native speakers. Therefore, only one symbol is needed in a broad transcription to indicate every t sound. If there is a need to transcribe narrowly in English, diacritic marks can be added to indicate that the t's in “tap,” “pat,” and “stem” differ slightly in pronunciation.

The International Phonetic Alphabet has not had the overwhelming success that its designers intended, and it is used less commonly in America than in Europe. Despite its acknowledged failings as a universal system for phonetic transcription, it is more widely employed than any other. One of its principal disadvantages when used in printing and typing is its utilization of a large number of special symbols in addition to the letters of the Roman alphabet that constitute its core. Modifications and substitutions are often made for reasons of economy and convenience.