The Extensions to the International Phonetic Alphabet for Disordered Speech, commonly abbreviated extIPA /ɛkˈstaɪpə/, are a set of letters and diacritics devised by the 1989 Kiel Convention and later by the International Clinical Phonetics and Linguistics Association (ICPLA) to augment the International Phonetic Alphabet for the phonetic transcription of disordered speech. Some of its symbols are also used to represent features of normal speech in IPA transcriptions, and are accepted for that purpose by the International Phonetic Association.
Many sounds found only in disordered speech are indicated with diacritics, though an increasing number of dedicated letters are used as well. Special letters are included to transcribe the speech of people with lisps and cleft palates. The extIPA repeats several traditional IPA diacritics that the ICPLA has found are unfamiliar to most speech pathologists but which transcribe features that are common in disordered speech. These include preaspiration ⟨ʰ◌⟩, linguolabials ⟨◌̼⟩, laminal fricatives [s̻, z̻], and ⟨*⟩ for a sound (segment or feature) that has no available symbol (letter or diacritic). The novel transcription ⟨ɹ̈⟩ is used for an English molar-r, as opposed to ⟨ɹ̺⟩ for an apical r; these articulations are acoustically indistinguishable and so are rarely identified in non-disordered speech.
