Back vowel

A back vowel is any in a class of vowel sound used in spoken languages. The defining characteristic of a back vowel is that the highest point of the tongue is positioned relatively back in the mouth without creating a constriction that would be classified as a consonant. Back vowels are sometimes also called dark vowels because they are perceived as sounding darker than the front vowels.^[1]

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

Near-back vowels are essentially a type of back vowels; no language is known to contrast back and near-back vowels based on backness alone.

The category "back vowel" comprises both raised vowels and retracted vowels.

Articulation

In their articulation, back vowels do not form a single category, but may be either raised vowels such as [u] or retracted vowels such as [ɑ].^[2]

Partial list

The back vowels that have dedicated symbols in the International Phonetic Alphabet are:

• close back unrounded vowel [ɯ]
• close back protruded vowel [u]
• near-close back protruded vowel [ʊ]
• close-mid back unrounded vowel [ɤ]
• close-mid back protruded vowel [o]
• open-mid back unrounded vowel [ʌ]
• open-mid back rounded vowel [ɔ]
• open back unrounded vowel [ɑ]
• open back rounded vowel [ɒ]

There also are back vowels that do not have dedicated symbols in the IPA:

• close back compressed vowel [ɯᵝ] or [uᵝ]
• near-close back unrounded vowel [ɯ̽] or [ʊ̜]
• near-close back compressed vowel [ɯ̽ᵝ] or [ʊᵝ]
• close-mid back compressed vowel [ɤᵝ] or [oᵝ]
• mid back unrounded vowel [ɤ̞] or [ʌ̝]
• mid back rounded vowel [o̞] or [ɔ̝]

As here, other back vowels can be transcribed with diacritics of relative articulation applied to letters for neighboring vowels, such as ⟨u̞⟩, ⟨o̝⟩ or ⟨ʊ̠⟩ for a near-close back rounded vowel.

Occurrence

According to PHOIBLE, the most common phonemic back vowel is /u/, occurring in approximately 88% of languages, while the most uncommon phonemic back vowel is /ɒ/, occurring in only 2% of recorded inventories.

Back vowel occurrences^[3]

Vowel	%
/u/	88
/o/	60
/ɔ/	35
/ʊ/	14
/ɑ/	7
/ɯ/	6
/ʌ/	4
/ɤ/	3
/ɒ/	2

See also

• Front vowel
• Central vowel
• List of phonetics topics
• Relative articulation