Vowels

Consonants are described by where the airway is blocked or squeezed. Vowels have little or no obstruction, so there is no "where it touches" to name. Instead we describe the shape of the open space in the mouth, using three questions: how high is the tongue, how far forward, and are the lips rounded?

The Three Dimensions

According to Wikipedia's article on vowels, a vowel is produced with little or no obstruction of the vocal tract, whereas a consonant has a constriction or closure somewhere along it. Phonologically, a vowel is the sound that forms the peak of a syllable.

Rounding usually reinforces back vowels, but some languages, such as French and German, have front rounded vowels. In English, the usual pairing holds: [i] is front and unrounded, [u] is back and rounded.

Try it

Say [i] (as in see) then [ɑ] (as in ah) slowly. Your jaw drops: that is height. Now say [i] then [u] (as in you) and watch your lips: they round for [u]. Your tongue also moves back, which you can feel if you keep your fingertip on your chin. (This exercise is mine; the labels are the source's.)

The Vowel Chart

The IPA plots height against backness on a trapezoid-shaped chart, with unrounded vowels to the left of rounded ones in each cell. Here are the main vowels from Wikipedia's chart (unrounded / rounded):

I have left out the open row. The summary of the chart I worked from was ambiguous there (it lists [a], [ɶ], [ä] and [ɑ], [ɒ]), and I would rather leave it to the Chapter 6 chart than guess.

Cardinal Vowels

Daniel Jones devised the cardinal vowel system in the early 20th century, building on earlier work by Alexander John Ellis and Alexander Melville Bell. There are eight primary cardinal vowels and 22 in total (9-22 are secondary). They are not the vowels of any language but a fixed measuring scale.

• Four corner vowels ([i], [a], [ɑ], [u]) are defined by articulation; the others are set at auditorily equal intervals between them.
• Jones held that using the system well needs training, with an expert or with recordings of each vowel.
• Ladefoged's experiments found trained phoneticians agreed closely near the cardinal values but diverged widely farther away. The system is usually taken to support about 16 primary and secondary vowels plus some central ones.

Different Kinds of Vowel

• Monophthong: the quality stays the same throughout, as in hit [ɪ].
• Diphthong: glides from one quality to another, as in boy [ɔɪ]. A triphthong glides through three. Whether a sequence counts as a diphthong or triphthong depends on whether it is analysed as one phoneme or several.
• Nasalised vowels: oral vowels that pick up nasality from a neighbouring nasal consonant, as in English hand. Nasal vowels are phonemically distinct, as in French /ɑ/ versus /ɑ̃/ (the velum of Chapter 2 at work).
• Long vowels contrast phonemically in languages such as Japanese, Finnish, Hungarian, Arabic and Latin. Vowels also lengthen non-distinctively when stressed or spoken slowly.

Wikipedia's other examples: ah /ɑː/, oh /oʊ/, and the tense-versus-lax pair mate and mat. The vowels of real English accents are the subject of Chapter 7.

Try It Yourself