Voiceless glottal fricative

Voiceless glottal fricative
h
IPA Number	146
Audio sample
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Encoding
Entity (decimal)	h
Unicode (hex)	U+0068
X-SAMPA	h
Braille
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Voiceless glottal approximant
h
ɦ̥
Audio sample
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Encoding
X-SAMPA	h_o
Braille
Image

The voiceless glottal fricative, sometimes called voiceless glottal transition or the aspirate,^[1][2] is a type of sound used in some spoken languages that patterns like a fricative or approximant consonant phonologically, but often lacks the usual phonetic characteristics of a consonant. The symbol in the International Phonetic Alphabet that represents this sound is ⟨h⟩, and the equivalent X-SAMPA symbol is h. However, [h] has been described as a voiceless vowel because in many languages, it lacks the place and manner of articulation of a prototypical consonant, as well as the height and backness of a prototypical vowel:

[h and ɦ] have been described as voiceless or breathy voiced counterparts of the vowels that follow them [but] the shape of the vocal tract [...] is often simply that of the surrounding sounds. [...] Accordingly, in such cases it is more appropriate to regard h and ɦ as segments that have only a laryngeal specification, and are unmarked for all other features. There are other languages [such as Hebrew and Arabic] which show a more definite displacement of the formant frequencies for h, suggesting it has a [glottal] constriction associated with its production.^[3]

An effort undertaken at the Kiel Convention in 1989 attempted to move glottal fricatives, both voiceless and voiced, to approximants.^[4][5] Also the approximant may be represented by the same symbol or ɦ̥.