vowels

Vowels are a class of speech sounds produced with an open vocal tract that allows air to flow freely, typically without major constriction. In most languages vowels are voiced and they form the nucleus of syllables, carrying the main audible weight of syllables. Their quality varies mainly with the position of the tongue and the shape of the lips.

Articulatory description centers on three primary dimensions: tongue height (high, mid, low), tongue backness (front, central, back), and lip rounding (rounded or unrounded). These factors combine to produce a system of distinct vowel qualities. Many languages also distinguish tenseness (tense vs lax) and, in some cases, contrastive length. Some languages feature additional voice qualities such as breathy or creaky voice vowels.

Vowels contrast with consonants in that they are typically produced with a relatively open vocal tract and often serve as the syllabic core. They can occur as monophthongs, maintaining a single quality over their duration, or as diphthongs and, in some languages, triphthongs, which glide from one vowel quality to another within a syllable.

Inventory and variation vary widely across languages. Some languages have small inventories of five to seven simple vowels, while others have many distinctions including nasalization, vowel length, vowel harmony, and distinct phonations. Vowel systems also interact with phonotactics and stress patterns, influencing syllable structure and rhythm.

Writing systems usually represent vowels with letters in alphabetic scripts, sometimes supplemented by diacritics to mark length, nasalization, tone, or rounding. Vowels thus play a central role in phonology, phonetics, and writing across languages.