Chapter 11.5: Vowels

Like consonants, vowels are made by expelling air from the lungs through the vibrating vocal cords and into the oral cavity. Unlike the consonants, however, when we make the vowel sounds we do not close or greatly obstruct the air flow. Instead, we move the tongue into various places and raise or lower our lower jaw, and by doing so, we alter the frequency of the vibrations caused by the air flow and vocal cords. The variations in frequency are perceived as different phonemes. In General American English twelve distinct vowel phonemes can be distinguished, as shown in the following chart.

The chart represents the inside of the mouth with the teeth towards the left. Where the chart says “front” is the front of the mouth, specifically the area just behind the teeth, the alveolar ridge. The right-hand side of the chart, which is labeled “back” is the back of the mouth, roughly where the velum, or soft palate, is. Similarly, the three sections labeled “high,” “mid,” and “low” represent the roof of the mouth down to the lower jaw. The symbols are placed at the various locations within the mouth where the tongue moves in order to make the relevant vowel sound. The symbols in the white area represent the vowels in which the tongue is fairly “tense” while saying them, while the symbols within the grayed area are made with a relaxed tongue. Finally, the four vowel symbols within the box in the back, high, and mid area are vowels which are pronounced while the lips are “rounded.” Further explanation of this terminology will be found below.

An interactive vowel chart, with audio examples, can be found here.

Distinctive Features

Vowels are distinguished by four distinctive features:

height: Vowel height can be high, mid, and low, depending on whether the tongue is near the roof of the mouth (i.e., high), or near the floor of the mouth. For example, say just the vowels of the words beet, bait, bat, concentrating on where your tongue is. The first has a high vowel, the second a mid vowel, and the third a low vowel.
frontness: Vowels can be front, central and back, depending on where the tongue is. English generally distinguishes only front and back vowels. For example, say just the vowels in the words bait and bought and feel the position of the tongue sliding forward and back against the roof of the mouth. Both are mid vowels, but the first is a front vowel and the second is a back vowel.
tenseness: Vowels can be tense or lax, depending again on the tongue. As examples, say beet, which has a tense vowel, and then say bit, which has a lax vowel. Tense and lax only applies to high and mid vowels. The low vowels do not have tense distinctions.
roundedness: Vowels can be rounded or unrounded depending on the shape of the lips. In English generally the front vowels are unrounded and the back vowels (at least the mid and high ones) are rounded. For example, say the vowels in beet and boot. Besides the tongue sliding back and forth to the front and back, you will notice that your lips become rounded to say boot but they are not rounded when you say beet.

In what follows I will describe the 15 vowel phonemes of English. All vowels are produced by expelling air through the oral cavity, with minimal restriction provided by tongue placement and lip rounding. All vowels are voiced.

High Vowels

front, tense, unrounded /i/. Examples: bee, beat, machine
front, lax, unrounded /ɪ/. Examples, bit, flip
back, tense, rounded /u/. Examples: moon, mood, rude
back, lax, rounded /ʊ/. Examples: put, foot

Mid Vowels

front, tense, unrounded /e/. Examples: bait, day, made, name.
front, lax, unrounded /ɛ/. Examples: bet, head, peck.
back, tense, rounded /o/: Examles: boat, hope, moan.
back, lax, rounded /ɔ/: Examples: bought, caught, hawk (Note: this phoneme is often not part of the Western American dialect)

Low Vowels

front, unrounded /æ/. Examples: cat, bat.
back, unrounded /ɑ/. Examples: cot, hock, pot, bother, father. (People with a Western American dialect will also pronounce bought, caught with this vowel instead of /ɔ/).

Two other vowel sounds occur

/ʌ/. This symbol represents is a central, mid, unrounded, lax vowel. For many Americans it does not contrast with the following vowel, but is used only for stressed vowels. Examples: cup, luck, love.
/ə/. This is the schwa, the reduced central >mid vowel found in most unaccented syllables. It comprises several different vowel sounds, all found in unaccented syllables, specifically [ə], as in about, sofa, occur, nation. And a slightly higher vowel, [ɨ], as in dishes, messes, rated, raided. For the purposes of this course you can transcribe both of these as /ə/ if you wish, but you should be aware of both symbols in case you see them elsewhere.

Diphthongs

All the above vowel sounds are monophthongs, that is, they are single vowel sounds. As such, they are distinguished from diphthongs, two vowels sounds spoken together in a single syllable. There are three phonemic diphthongs in American English. Each consists of a main vowel, followed by an offglide which is either a front or back high vowel. (Note: The “ph” in the words monophthong and diphthong can be pronounced either as an [f] or a [p]).

/aɪ/. This sound starts with /a/, a low front vowel very similar to /æ/, followed by a glide toward /ɪ/. Examples: rice, wife, eye.
/aʊ/. This sound also starts with /a/, but the glide is the rounded back vowel /ʊ/. Examples: house, brown, cow.
/ɔɪ/. This sound starts with the mid back rounded vowel /ɔ/ before moving to the front unrounded /ɪ/. Examples: joy, boy, boil.

A note on the pronunciations of monophthongs as diphthongs in American English: Most speakers of American English pronounce the simplex vowels like /e/ and /o/ as the diphthongs [eɪ] and [oʊ]. As a result, some textbooks and online resources give represent these vowels in IPA as diphthongs. In British resources /o/ is often represented as [ɛʊ]. We will make these distinctions when necessary, but otherwise will treat these vowels as if they were pronounced simply /e/ and /o/.