History of the International Phonetic Alphabet

[23] The equivalent part of the 1904 English edition said: [I]t must remain a general principle to leave out everything self-evident, and everything that can be explained once for all.

This allows us to dispense almost completely with the modifiers, and with a good many other signs, except in scientific works and in introductory explanations.

⟨ᵷ, ʒ⟩ were removed from the chart and instead only mentioned as having "been suggested for a Circassian dental hiss [sibilant] and its voiced correspondent".

Also added were dedicated letters for the central vowels, ⟨ɨ, ʉ, ɘ, ɵ, ᴈ, ʚ⟩, which appeared again in Trofimov & Jones (1923), p. 40 and in the chart in Le Maître Phonétique from 1926 to 1927, though without the Council's approval.

The book also mentioned letters "already commonly used in special works", some of which had long been part of the IPA but others which "have not yet been definitively adopted":[42] It also introduced several new suprasegmental specifications:[44] It recommended the use of a circumflex for the Swedish grave accent, as in [ˆandən] ("the spirit").

In 1960, A. C. Gimson wrote to a colleague: Paul Passy recognized the need for letters for the various clicks in the July–August 1914 number of Le Maître Phonétique and asked for suggestions.

During this interval, Professor Daniel Jones himself invented the four letters, in consultation with Paul Passy and they were all four printed in the pamphlet L'Écriture Phonétique Internationale published in 1921.

I have consulted Professor Jones in this matter, and he accepts responsibility for their invention, during the period of the First World War.

[45] In April 1925, 12 linguists led by Otto Jespersen, including IPA Secretary Daniel Jones, attended a conference in Copenhagen and proposed specifications for a standardized system of phonetic notation.

[52] Nonetheless, the following additions recommended by the Conference were approved in 1927:[53] In 1928, the following letters were adopted:[39] The following letters, which had appeared in earlier editions, were repeated or formalized:[39] Jones (1928) also included ⟨ɱ⟩ for a labiodental nasal, ⟨ɾ⟩ for a dental or alveolar tap, ⟨ʞ⟩ for a palatal ('velar') click, and the tonal notation system seen in Association phonétique internationale (1921), p. 9.

For the Swedish and Norwegian compound tones he recommended "any arbitrarily chosen mark", with the illustration [˟andən] ("the spirit").

[56] The use of tie bars ⟨◌͡◌, ◌͜◌⟩ was allowed for synchronous articulation in addition to affricates, as in ⟨m͡ŋ⟩ for simultaneous [m] and [ŋ], which was approved in 1937.

[69] Conceived by John S. Kenyon, the letter was in itself a combination of ⟨ə⟩ and the hook for retroflex consonants approved by the IPA in 1927.

Since its introduction in 1935, the letter was widely adopted by American linguists and the IPA had been asked to recognize it as part of the alphabet.

AFFRICATES can be written as digraphs, as ligatures, or with slur marks; thus ts, tʃ, dʒ: ʦ ʧ ʤ: t͡s t͡ʃ d͡ʒ.

Diacritics ⟨◌̢⟩ (subscript, not attached) for retroflexion, ⟨◌̮⟩ for palatalization, and ⟨◌̯⟩ for indicating non-fricative continuant were proposed but rejected.

[10] It was at this convention that it was decided that the Handbook of the IPA (International Phonetic Association 1999) would be written and published to supersede the 1949 Principles.

[84] A drastically renewed chart of the alphabet reflecting decisions made at the convention appeared later in the year.

Additions were:[85] Tone, which had been indicated with an iconic line preceding the syllable or above or below the vowel, was now written one of two ways: with a similar iconic line following the syllable and anchored to a vertical bar, as in ⟨˥, ˦, ˧˩˨⟩ (Chao's tone letters), or with more abstract diacritics written over the vowel (acute = high, macron = mid, grave = low), which could be compounded with each other, as in ⟨ə᷄, ə᷆, ə᷈, ə̋, ə̏⟩.

The alternative raised and lowered diacritics ⟨◌̣, ◌̨⟩ were eliminated in favour of ⟨◌̝, ◌̞⟩, which could now be attached to consonants to denote fricative or approximant, as in ⟨ɹ̝, β̞⟩.

The practice of placing a superscript letter to indicate the resemblance to a sound, previously illustrated by ⟨ʃˢ⟩, was no longer explicitly recommended.

(iii) When the introduction of a single, diacritic obviates the necessity for designing a number of new symbols (as, for instance, in the representation of nasalized vowels)".

[89] The principles also adopted the recommendation of enclosing phonetic transcriptions in square brackets [ ] and phonemic ones in slashes / /,[89] a practice that emerged in the 1940s.

The outer stroke of the letter for a bilabial click ⟨ʘ⟩ was modified from a circle with a uniform line width to the shape of uppercase O.

[101] The 1999 Handbook of the International Phonetic Association was the first book outlining the specifications of the alphabet in 50 years, superseding the 1949 Principles of the IPA.

[104] It abandoned the 1949 Principles' recommendation of alternating ⟨⟩ and ⟨ɡ⟩ for ordinary and advanced velar plosives, and acknowledged both shapes as acceptable variants.

[106] In 2011, it was proposed that ⟨ᴀ⟩ be added to represent the open central unrounded vowel, but this was declined by the Council the following year.

[108] In 2016, three versions of a revised chart dated 2015 were released online, each with the characters rendered in a different typeface (IPA Kiel/LS Uni developed by Linguist's Software, Doulos SIL, and DejaVu Sans).

[110] In 2018, another slightly modified chart in different fonts was released, this time also in TeX TIPA Roman developed by Rei Fukui, which was selected as best representing the IPA symbol set by the Association's Alphabet, Charts and Fonts committee, established the previous year.

[111] In 2020, another set of charts was released, with the only changes being minor adjustments in the layout, and Creative Commons icons replacing the copyright sign.