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A close vowel is a type of vowel sound used in many spoken languages. The defining characteristic of a close vowel is that the tongue is positioned as close as possible to the roof of the mouth without creating a constriction that would be classified as a consonant.

This term is prescribed by the International Phonetic Association. Close vowels are often referred to as high vowels, as in the Americanist phonetic tradition, because the tongue is positioned high in the mouth during the articulation of a close vowel.

The six close vowels identified within the International Phonetic Alphabet are:

• close front unrounded vowel [i]
• close front rounded vowel [y]
• close central unrounded vowel [ɨ]
• close central rounded vowel [ʉ]
• close back unrounded vowel [ɯ]
• close back rounded vowel [u]

In the context of the phonology of any particular language, a high vowel can be any vowel that is more close than a mid vowel. That is, close-mid vowels, near-close vowels, and close vowels can all be considered high vowels.