Vowels beside dots are: unrounded • rounded
A near-close vowel or a near-high vowel is any in a class of vowel sound used in some spoken languages. The defining characteristic of a near-close vowel is that the tongue is positioned similarly to a close vowel, but slightly less constricted.
Other names for a near-close vowel are lowered close vowel and raised close-mid vowel, though the former phrase may also be used to describe a vowel that is as low as close-mid (sometimes even lower); likewise, the latter phrase may also be used to describe a vowel that is as high as close.
Near-close vowels are also sometimes described as lax variants of the fully close vowels, though, depending on the language, they may not necessarily be variants of close vowels at all.
It is rare for languages to contrast a near-close vowel with a close vowel and a close-mid vowel based on height alone. An example of such language is Danish, which contrasts short and long versions of the close front unrounded /i/, near-close front unrounded /e̝/ and close-mid front unrounded /e/ vowels, though in order to avoid using any relative articulation diacritics, Danish /e̝/ and /e/ are typically transcribed with phonetically inaccurate symbols /e/ and /ɛ/, respectively. This contrast is not present in Conservative Danish, which realizes the latter two vowels as, respectively, close-mid [e] and mid [e̞].
It is even rarer for languages to contrast more than one close/near-close/close-mid triplet. For instance, Sotho has two such triplets: fully front /i–ɪ–e/ and fully back /u–ʊ–o/. In the case of this language, the near-close vowels /ɪ, ʊ/ tend to be transcribed with the phonetically inaccurate symbols /ɨ, ʉ/, i.e. as if they were close central.
The near-close vowels that have dedicated symbols in the International Phonetic Alphabet are:
The Handbook of the International Phonetic Association defines these vowels as mid-centralized (lowered and centralized) equivalents of, respectively, [i], [y] and [u], therefore, an alternative transcription of these vowels is [i̽, y̽, u̽] or the more complex [ï̞, ÿ˕, ü̞]; however, they are not centralized in all languages - some languages have a fully front variant of [ɪ] and/or a fully back variant of [ʊ]; the exact backness of these variants can be transcribed in the IPA with [ɪ̟, ʊ̠], [i̞, u̞] or [e̝, o̝].
There also are near-close vowels that don't have dedicated symbols in the IPA:
(IPA letters for rounded vowels are ambiguous as to whether the rounding is protrusion or compression. However, transcription of the world's languages tends to pattern as above.)
Other near-close vowels can be indicated with diacritics of relative articulation applied to letters for neighboring vowels, such as ⟨ɪ̟⟩, ⟨i̞⟩ or ⟨e̝⟩ for a near-close front unrounded vowel, or ⟨ʊ̠⟩, ⟨u̞⟩ or ⟨o̝⟩ for a near-close back rounded vowel.