Central vowel

A central vowel is a special kind of vowel sound made when the tongue is in the middle position, not too far forward and not too far back in the mouth. This middle position is between where we place our tongue for front vowels, like the "i" in "sit," and back vowels, like the "u" in "put."

The word "central" describes this middle place for the tongue, called the backness dimension. It is different from another idea called "mid," which talks about how high or low the tongue is, called the height dimension. So, a central vowel is about where the tongue is side to side, not how high or low it is.

In a big study of sounds from many languages, two central vowel sounds are very common. These sounds are shown with special symbols: [ə] and [ɨ]. They appear in many languages around the world. Other central vowel sounds exist too, but they are used much less often in different languages.

Articulation and acoustics

Central vowels are made by placing the tongue in a middle position, not too far forward and not too far back. This middle position can vary a little between different languages.

The International Phonetic Alphabet (IPA) has a chart that shows different vowel sounds. On this chart, the horizontal line shows how far forward or backward the tongue is, and the vertical line shows how high or low the tongue is. Central vowels sit in the middle of the horizontal line.

IPA transcription

On the International Phonetic Alphabet vowel chart, central vowels are found in the middle column between front and back vowels. When we need to be more specific, we can use special marks to show small changes in how these vowels sound.

The central vowels that have their own special symbols include:

• close central unrounded vowel [ɨ]
• close central rounded vowel [ʉ]
• close-mid central unrounded vowel [ɘ] (also written as ⟨ë⟩)
• close-mid central rounded vowel [ɵ] (also written as ⟨ö⟩)
• mid central vowel [ə]
• open-mid central unrounded vowel [ɜ] (also written as ⟨ɛ̈⟩)
• open-mid central rounded vowel [ɞ] (also written as ⟨ɔ̈⟩)
• near-open central vowel [ɐ]

Different places may use these symbols in slightly different ways. For example, some use [ɜ] for a strong central vowel and [ə] for a weaker one, while others might use [ə] for a fully strong central vowel too.

Central vowel sounds that do not have their own special symbols are usually shown with marks that indicate small changes. Some examples are:

• near-close central unrounded vowel [ɨ̞], [ɪ̈], [ɪ̠] or [ɘ̝]
• near-close central rounded vowel [ʉ̞], [ʊ̈], [ʊ̟] or [ɵ̝]
• near-close central vowel with a special rounding (as in some Swedish sounds) might be written as [ʏ̈]
• mid central unrounded vowel [ɘ̞] or [ɜ̝] (often just written as ⟨ə⟩)
• mid central rounded vowel [ɵ̞] or [ɞ̝] (often just written as ⟨ɵ⟩)
• open central unrounded vowel [ä] (sometimes written as ⟨ä⟩)
• open central rounded vowel [ɒ̈]