Roundedness

In phonetics, vowel roundedness describes how the lips are shaped when making vowel sounds. It refers to whether the lips are rounded or spread apart during speech. Rounded vowels are shown on the right side of the International Phonetic Alphabet chart, while unrounded vowels are on the left. For example, in most English words, the vowel sound in "too" is rounded, while the sound in "see" has spread lips.

Different languages use rounded and unrounded vowels in various ways. While many languages have front vowels with spread lips and back vowels with rounded lips, some, like French and German, use both rounded and unrounded sounds for front vowels. Others, such as Vietnamese, do this for back vowels, and Turkish uses both for front and back vowels.

The way lips are shaped can change how a vowel sounds. When making a rounded back vowel, the lips form a small, round opening. Unrounded vowels are made with spread or relaxed lips. This difference helps our ears tell vowels apart. One language, Alekano, is special because it only uses unrounded vowels.

Typology

Vowel roundedness describes how the lips are shaped when making vowel sounds. In the International Phonetic Alphabet, rounded vowels appear on the right in each pair, while unrounded vowels are on the left. For example, the vowel [u] is closely rounded, while [i] is fully spread.

The height of the vowel affects how much the lips are rounded or spread. Open vowels, like [a], usually have a neutral lip position. Back vowels show a range from neutral to closely rounded, while front vowels are typically unrounded but can have varying degrees of spreading.

Transcription

When writing sounds for vowels, special symbols can help show how the lips are shaped. Sometimes small letters above the main letter are used to show if the lips are pushed out or pulled in. There are also old symbols that can show different kinds of rounding.

We can use special marks to show central vowels, which are sounds made in the middle of the mouth. These marks help make the sound clearer. The tables below show different ways to write these sounds using these special symbols.

Main article: nonstandard symbols in the IPA

Rounding and labialization

When we make certain vowel sounds, we often round our lips. This rounding can affect the sounds of nearby consonants, and vice versa. For example, in Vietnamese, after certain rounded vowel sounds like /u/ and /o/, the consonant sounds /k/ and /ŋ/ change shape and become labialized, meaning the lips are rounded during their pronunciation.

In some languages, such as the Northwest Caucasian languages spoken in southern Russia and Georgia, and Arrernte from central Australia, rounded vowels have influenced nearby consonants so much that they created new consonant sounds with rounded lips, while the vowels themselves lost their rounding.

Roundedness in English

In some dialects of British English, like the Cardiff dialect, Geordie, and Port Talbot English, as well as in General South African English and New Zealand English, certain vowel sounds change based on whether the lips are rounded. This creates pairs of sounds that are different but close to each other.

For example, in Standard Southern British English and Western Pennsylvania English, words like nut and not sound different mainly because of rounding. These differences can also be influenced by other factors like the height or shape of the mouth. In Scottish English, these sounds can change in subtle ways, making some words sound quite different depending on the rounding of the lips.