The International Phonetic Alphabet (unofficially’though commonly’abbreviated IPA) is an alphabetic system of phonetic notation based primarily on the Latin alphabet. It was devised by the International Phonetic Association as a standardized representation of the sounds of oral language. The IPA is used by lexicographers, foreign language students and teachers, linguists, speech-language pathologists, singers, actors, constructed language creators, and translators. The IPA is designed to represent only those qualities of speech that are part of oral language: phones, phonemes, intonation, and the separation of words and syllables. To represent additional qualities of speech, such as tooth gnashing, lisping, and sounds made with a cleft palate, an extended set of symbols called the Extensions to the IPA may be used. IPA symbols are composed of one or more elements of two basic types, letters and diacritics. For example, the sound of the English letter may be transcribed in IPA with a single letter, , or with a letter plus diacritics, , depending on how precise one wishes to be. Often, slashes are used to signal broad or phonemic transcription; thus, is less specific than, and could refer to, either or , depending on the context and language. Occasionally letters or diacritics are added, removed, or modified by the International Phonetic Association. As of the most recent change in 2005, there are 107 letters, 52 diacritics, and four prosodic marks in the IPA. These are shown in the current IPA chart, posted below in this article and at the website of the IPA.