Open front unrounded vowel

Open front unrounded vowel
a
IPA Number	304
Audio sample
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Encoding
Entity (decimal)	a
Unicode (hex)	U+0061
X-SAMPA	a
Braille

IPA: Vowels
Front Central Back Close i y ɨ ʉ ɯ u Near-close ɪ ʏ ʊ Close-mid e ø ɘ ɵ ɤ o Mid e̞ ø̞ ə ɤ̞ o̞ Open-mid ɛ œ ɜ ɞ ʌ ɔ Near-open æ ɐ Open a ɶ ä ɑ ɒ
IPA help  audio full chart template Legend: unrounded • rounded

The open front unrounded vowel, or low front unrounded vowel,^[1] is a type of vowel sound used in some spoken languages. It is one of the eight primary cardinal vowels, not directly intended to correspond to a vowel sound of a specific language but rather to serve as a fundamental reference point in a phonetic measuring system.^[2]

The symbol in the International Phonetic Alphabet (IPA) that represents this sound is ⟨a⟩, and in the IPA vowel chart it is positioned at the lower-left corner. However, the accuracy of the quadrilateral vowel chart is disputed, and the sound has been analyzed acoustically as extra-open at a position where the front/back distinction has lost its significance. There are also differing interpretations of the exact quality of the vowel: the classic sound recording of [a] by Daniel Jones is slightly more front but not quite as open as that by John Wells.^[3]

In practice, the symbol ⟨a⟩ is often used to represent an open central unrounded vowel.^[4] This is the usual practice, for example, in the historical study of the English language. The loss of separate symbols for open and near-open front vowels is usually considered unproblematic, because the perceptual difference between the two is quite small, and very few languages contrast the two. If there is a need to specify the backness of the vowel as fully front one can use the symbol ⟨æ̞⟩, which denotes a lowered near-open front unrounded vowel, or ⟨a̟⟩ with the IPA "advanced" diacritic.

The Hamont-Achel dialect of Limburgish has been reported to contrast long open front, central and back unrounded vowels.^[5] This is extremely unusual.