International Phonetics Alphabet and its history

       The International Phonetic Alphabet (IPA) is an alphabetic system of phonetic notationbased primarily on the Latin alphabet. It was devised by the International Phonetic Associationas a standardized representation of the sounds of spoken language. The IPA is used byforeign language students and teachers, linguists, speech pathologists and therapists, singers,actors, lexicographers, conlangers and translators.

     The IPA is designed to represent only those qualities of speech that are distinctive in spoken language: 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 ‹t› may be transcribed in IPA with a single letter, [t], or with a letter plus diacritics, [t̺ʰ], depending on how precise one wishes to be. Occasionally letters or diacritics are added, removed, or modified by the International Phonetic Association. As of 2008, there are 107 letters, 52 diacritics, and four prosodic marks in the IPA.

     In 1886, a group of French and British language teachers, led by the French linguist Paul Passy, formed what would come to be known from 1897 onwards as the International Phonetic Association (in French, l’Association phonétique internationale). Their original alphabet was based on a spelling reform for English known as the Romic alphabet, but in order to make it usable for other languages, the values of the symbols were allowed to vary from language to language. For example, the sound [ʃ] (the sh in shoe) was originally represented with the letter ‹c› in English, but with the letter ‹x› in French. However, in 1888, the alphabet was revised so as to be uniform across languages, thus providing the base for all future revisions.

     Since its creation, the IPA has undergone a number of revisions. After major revisions and expansions in 1900 and 1932, the IPA remained unchanged until the IPA Kiel Convention in 1989. A minor revision took place in 1993, with the addition of four letters for mid-central vowels and the removal of letters for voiceless implosives. The alphabet was last revised in May 2005, with the addition of a letter for a labiodental flap. Apart from the addition and removal of symbols, changes to the IPA have consisted largely in renaming symbols and categories and in modifying typefaces.

     Extensions of the alphabet are relatively recent; "Extensions to the IPA" was created in 1990 and officially adopted by the International Clinical Phonetics and Linguistics Association in 1994.

       The general principle of the IPA is to provide one letter for each distinctive sound (speech segment). This means that it does not use combinations of letters to represent single sounds, the way English does with ‹sh› and ‹ng›, or single letters to represent multiple sounds the way ‹x› represents /ks/ or /ɡz/ in English. There are no letters that have context-dependent sound values, as ‹c› does in English and other European languages, and finally, the IPA does not usually have separate letters for two sounds if no known language makes a distinction between them, a property known as "selectiveness".

      Among the symbols of the IPA, 107 letters represent consonants and vowels, 31diacritics are used to modify these, and 19 additional signs indicate suprasegmentalqualities such as length, tone, stress, and intonation.

      The letters chosen for the IPA are meant to harmonize with the Latin alphabet. For this reason, most letters are either Latin or Greek, or modifications thereof. However, there are letters that are neither: for example, the letter denoting the glottal stop, ‹ʔ›, has the form of a "gelded" question mark, and derives originally from anapostrophe. In fact, there are a few letters, such as that of the voicedpharyngeal fricative, ‹ʕ›, which, though modified to fit the Latin alphabet, were inspired by other writing systems (in this case, the Arabic letter ﻉ‎, `ain).

     Despite its preference for harmonizing with the Latin alphabet, the International Phonetic Association has occasionally admitted letters that do not have this property. For example, before 1989, the IPA letters for click consonants were ‹ʘ›, ‹ʇ›, ‹ʗ›, and ‹ʖ›, all of which were derived either from existing IPA letters, or from Latin and Greek letters. However, except for ‹ʘ›, none of these letters was widely used amongKhoisanists or Bantuists, and as a result they were replaced by the more widespread symbols ‹ʘ›, ‹ǀ›, ‹ǃ›, ‹ǂ›, and ‹ǁ› at the IPA Kiel Convention in 1989. Although the IPA diacritics are fully featural, there is little systemicity in the letter forms. A retroflex articulation is consistently indicated with a right-swinging tail, as in ‹ɖ ʂ ɳ›, and implosion by a top hook, ‹ɓ ɗ ɠ›, but other pseudo-featural elements are due to haphazard derivation and coincidence. For example, all nasal consonants but uvular ‹ɴ› are based on the form ‹n›: ‹m ɱ n ɲ ɳ ŋ›. However, the similarity between ‹m› and ‹n› is a historical accident, ‹ɲ› and ‹ŋ› are derived from ligatures of gn and ng, and ‹ɱ› is an ad hoc imitation of‹ŋ›. In none of these is the form consistent with other letters that share these places of articulation.[citation needed]

     Some of the new letters were ordinary Roman letters typeset "turned" (= upside-down) (e.g. ʎ ɥ ə ɔ ɹ ᴚ), which was easily done beforemechanical typesetting machines came into use.

     The International Phonetic Alphabet is based on the Latin alphabet, using as few non-Latin forms as possible. The Association created the IPA so that the sound values of most consonant letters taken from the Latin alphabet would correspond to "international usage". Hence, the letters ‹b›, ‹d›, ‹f›, (hard) ‹ɡ›, (non-silent) ‹h›, (unaspirated) ‹k›, ‹l›, ‹m›, ‹n›, (unaspirated) ‹p›, (voiceless) ‹s›, (unaspirated) ‹t›, ‹v›, ‹w›, and ‹z›have the values used in English; and the vowel letters from the Latin alphabet (‹a›, ‹e›, ‹i›, ‹o›, ‹u›) correspond to the sound values of Latin: [i]is like the vowel in machine, [u] is as in rule, etc. Other letters may differ from English, but are used with these values in other European languages, such as ‹j›, ‹r›, and ‹y›.

     This inventory was extended by using capital or cursive forms, diacritics, and rotation. There are also several derived or taken from the Greek alphabet, though the sound values may differ. For example, ‹ʋ› is a vowel in Greek, but an only indirectly related consonant in the IPA. Two of these (‹θ› and ‹χ›) are used unmodified in form; for others (including ‹β›, ‹ɣ›, ‹ɛ›, ‹ɸ›, and ‹ʋ›) subtly different glyph shapes have been devised, which may be encoded in Unicode separately from their "parent" letters.

     The sound values of modified Latin letters can often be derived from those of the original letters. For example, letters with a rightward-facing hook at the bottom represent retroflex consonants; and small capital letters usually represent uvular consonants. Apart from the fact that certain kinds of modification to the shape of a letter generally correspond to certain kinds of modification to the sound represented, there is no way to deduce the sound represented by a symbol from its shape (unlike, for example, in Visible Speech).

     Beyond the letters themselves, there are a variety of secondary symbols which aid in transcription. Diacritic marks can be combined with IPA letters to transcribe modified phonetic values or secondary articulations. There are also special symbols for suprasegmental features such asstress and tone that are often employed.