What is a vowel?

A vowel is a sound that we make by vibrating our vocal cords and changing the shapes of our mouth, jaw, and tongue, while not interrupting the flow of air. This is different than consonants, which are formed by interfering with the flow of air in order to make a consonant sound. Additionally, vowels are more sonorous, or are made with more energy, than consonants.

How many vowels are there in American English?

Common estimates of vowels for American English are from 14 to 16.

If we count 16 vowels total, these vowels are:

Aren't there only five vowels?

There are five vowel letters in the English alphabet: a, e, i, o, and u. The letters w and y are sometimes considered to be vowels in the English alphabet, since they can represent either a consonant or a vowel sound.

Even though there are five to seven letters that we can use to represent vowel sounds, depending on the dialect there are 12 to 14 vowel sounds in American English, which is more than double the vowel letters in the English alphabet. As a result, these letters all represent more than one sound.

Letter	Phoneme	Examples
a
	,
e
i
o
u

As you can see, there are many more vowel sounds than vowel letters. When linguists refer to vowels, they are talking about the specific vowel sounds, not the vowel letters that we use in writing English. Since the alphabet we use is derived from the Roman alphabet, it wasn't originally designed for use with English's many vowels. Additionally, even if it were, there have been many changes over time, and as a result the vowels that were used in Old and Middle English are not the same exact ones we use today. As a result, we are using up to seven letters to represent up to fourteen vowel sounds.

How can we classify vowels?

There are four main ways we can classify vowel sounds: height, backness, roundedness, and tenseness.

Height

The height characteristic refers to how high or low the tongue is raised in the mouth when making the vowel. If the tongue is raised almost all the way to the roof of the mouth when making a vowel sound, the height is high, and we refer to this vowel as a high vowel. The vowels and are high vowels. Try saying these vowels and notice that your tongue raises when you do.

If the tongue is lowered to the bottom of the mouth when making a vowel sound, the vowel height is low, and we refer to this vowel as a low vowel. The vowel is a low vowel. Try saying it and feel your tongue dropping towards the bottom of your mouth. Other vowels are neither high or low vowels, since the tongue position when making them is somewhere between the top and the bottom of the mouth. If the tongue is in the middle when saying a vowel, like , we could say that it is a mid vowel. If it is between the high and mid position, we could say it is a mid-high vowel, like , and if it is between the low and mid position, we can refer to it as a low-mid vowel like .

In the table below, some of the vowels in American English have been included and arranged based on their height.

High
Mid
Low

Backness

In addition to moving the tongue up and down to change the way vowels sound, we can move the tongue forwards and backwards within our mouth to affect the sound. If we move our tongue body forward in the mouth while saying a vowel, we can describe this vowel as a front vowel. The vowel is a front vowel. If we move our tongue body all the way back in our mouth when saying a vowel, we can describe that vowel as a back vowel. The vowel is a back vowel. Additionally, just like with height, many vowels are pronounced with the tongue position somewhere in between being fully moved forward and being fully pulled back. A vowel where the tongue is balanced and pulled neither forwards nor backwards can be referred to as a central vowel, like the .

The table below builds on the previous table, and also shows how these vowels are classified based on their backness (or frontness).

	Front	Central	Back
High
Mid
Low

Diagramming Height and Backness

In order to represent the vowels, we can use a vowel diagram. This shows vowels distinguished by two categories. The first category is vowel height, or how high the tongue is raised in the mouth when the vowel is made. The second category is backness, or how far back the tongue is in the mouth when the vowel is made.

In the chart above, we can see that there are two dimensions, one for vowel height, and the other for backness. The shape of the diagram represents the mouth, wider at the front and narrower towards the back.

Vowels that are pronounced by pushing the root of the tongue body forward in the mouth are front vowels, those that are neither front nor back are mid vowels, and vowels that are pronounced by pulling the body of the tongue back in the mouth are back vowels.

In the chart above we can also look at vowel height. High vowels, which made with a raised tongue, occur closer to the top of the chart. Central vowels are made in the center. Low vowels are made with the tongue in the bottom of the mouth, and a more open mouth. Low vowels are also known as open vowels.

Roundedness

The chart can also be used to indicate another quality of the vowels, roundedness. In American English, as the vowel height of a back vowel increases, the amount of roundedness it has also increases. The vowels , , , and all have some degree of roundedness. Since is the highest, it is much rounder compared to , which is a back vowel that is made with a lower tongue position. The rounded vowels have been indicated on the vowel diagram with a dotted line.

Tenseness

Tenseness has to do with the muscular tension used to say a vowel. In American English, vowels can be classified as either tense or lax. A tense vowel is made with a lot of muscular tension. A lax vowel is a vowel that is not made with increased muscular tension. This tension occurs in the lips as well as the tongue muscles. Many of the tense vowels in English tend to be longer than lax vowels, although this is not always the case.

Tense vowels in American English are pronounced with off-glides. This means that when a tense vowel is said, there is slight movement, or gliding, of the mouth into a position that changes the vowel sound. As a result, after the vowels and are said, American English speakers quickly glide into a different vocal tract position. When they start saying , they then glide into the position for , resulting in . When they start saying , they then glide into the position for , resulting in . This also occurs with the vowels and to some extent, so that they may often sound like and when they are pronounced.

The tense vowels in American English are:

The tense diphthongs in American English are:

The lax vowels in American English are:

Tense vowels have been bolded on the vowel diagram.

Vowel length

What are short and long vowels?

There are two different concepts to which the terms "short vowels" and "long vowels" can be applied. The concept that is familiar to most people is the idea that some vowels in English are long vowels, and others are short vowels. In this approach, which is frequently taught to children in schools, long vowels "say their name". The long vowels in this approach are considered to be , , , , and . The short vowels are all the other 11 vowels. The "long" and "short" vowel concept is often used when trying to teach spelling patterns in English. Some students are taught about the "magic e". The idea of the "magic e" rule is that if a word contains a short vowel and ends in a consonant, adding "magic e" will cause the new word to be pronounced with a long vowel.

Spelling Transformations with "Magic E"

Letter	"Short" Vowel	"Long" Vowel (After Adding "Magic E")
A
I
E
O
U

Teaching this rule can be helpful in some cases, but of course, there are exceptions to the "magic e" rule. For instance, although

, a white bird, has the sound known as "short u", , the word is is spelled the same way, but pronounced with a "long o". Additionally, using this type of long and short vowel system is confusing because there are more than 10 vowels in English, so there are other vowel sounds that just get left out in vowel limbo.

The vowel system taught in school refers to some of the vowels as "long vowels" because a long time ago, those vowels did represent long vowels. Those vowels were held for twice as long as short vowels, and the primary distinction between the short vowels and long vowels was actually the vowel length and not other characteristics like vowel height, backness, tenseness, and roundedness. However, during the history of English there was a Great Vowel Shift during which these long vowels changed in qualities other than vowel length. As a result of the historical pronunciation of these vowels, children in school are still taught about "long vowels" vs "short vowels", even though the distinction isn't based only on the actual length of the vowel sounds.

This way of classifying vowels is very different than how linguists speak of "short" and "long" vowels. Although the "long" vowels discussed above are held for a longer time, part of the reason they have a longer duration is that many of them are actually not pure vowels, but combinations of a pure vowel plus a glide. Saying more than one vowel in a sequence instead of saying just one takes longer. When linguists speak of vowel length they are interested in the length of pure vowels. Linguists can, and do, refer to certain vowels as short and long; for instance, on average is longer than , the other qualities that have been discussed above are more important when English speakers are trying to distinguish one vowel from another.

Measuring Vowel Length

Linguists can refer to short and long vowel length, and there is variability between how long different vowels are in English. For example, is longer than , and is longer than , which is the shortest vowel in English. Additionally, there are some other rules, like tense vowels tend to be shorter than lax vowels (an exemption is ae?), and vowels that are in a syllable which ends in a voiced sound are longer than the same vowel in a syllable that ends in a voiceless sound (

is longer than ). Knowing about and using these guidelines will certainly help to make your accent easier to understand. However, for people who are trying to make their accent more understandable, focusing on the vowel qualities that were discussed previously -- height, backness, roundness, and tenseness -- should be the first areas to focus on when working on your pronunciation in order to make a greater impact.

Monophthongs and Diphthongs

In English, vowels can occur by themselves or with other vowels. If a vowel appears by itself in a syllable, we can call this a monophthong. If there are two vowels in a syllable, we can refer to that as a diphthong.

Monophthongs

A monophthong is just one vowel sound that occurs in a syllable. We can also say monophthongs are "pure" vowels. When these vowels are made, the mouth, lips, jaw, and other parts of the vocal tract get into the position to create this one vowel, and do not change into a position for another vowel.

Diphthongs

Diphthongs are combinations of two vowel sounds said together, where one of them is emphasized more than the other. In order to say them, a speaker first gets their vocal tract in position to say one vowel sound, and then quickly changes the position of their lips, jaws, tongue, and other speech articulators in order to change their vocal tract so that they will make a different vowel sound. This change occurs very quickly and is referred to as vowel gliding. In American English, there are several different diphthongs. All American English diphthongs contain either or , and the first vowel of the diphthong receives more emphasis than the second. The American English diphthongs are , , and .

Semi-vowels

Semi-vowels share properties of both consonants and vowels. There are two semi-vowels in English, , which is represented with the letter y, and , which is represented with the letter w. Semi-vowels are created by arranging parts of the vocal tract like the tongue, lips, and jaw in a position that can be used to create a vowel sound. However, when a semi-vowel is made, more movement is involved. For instance, moving our tongue back and forth when our mouth is in the position to say produces the sound. Similarly, if we position our mouths to say and move our lips the sound produced is similar to the sound.

Another difference between semi-vowels and vowels is that although semi-vowels are produced similarly to vowels, they cannot make up the nucleus of a syllable. As an example, the words

or each begin with a semi-vowel that proceeds a vowel, which is the syllable nucleus.

Due to the gliding movement used in making them, semi-vowels are also referred to as glides.

Special Vowel Characteristics

The Schwa

American English is a stress-timed language, which means that the stress, or emphasis, for each syllable is not always the same. Some syllables will receive more stress than others. If a syllable is a stressed syllable, the vowel it contains will be longer, louder, higher, and distinct. If a syllable is an unstressed syllable, the vowel it contains will be shorter, quieter, have a lower pitch, and be less distinct. The vowels in unstressed syllables will generally be , , and most commonly .

The schwa is a mid central vowel sound. It's very common in unstressed syllables because it is easier and faster to make due to its centralized position. However, many non-native speakers of American English don't use this sound at all, even though it is the most common vowel, because they aren't aware it exists. Instead, they spend time trying to make sure their vowels sound very distinct. Doing this makes it more obvious they are non-native speakers and actually makes them harder to understand since native speakers don't do this and as a result, aren't used to hearing all the vowel sounds spoken distinctly. In order to make the schwa sound, make sure that when saying unstressed syllables you aren't taking the time to move your vocal tract in ways to make distinct sounds like , , and . For more information on the vowel, you can check out our post on schwa .

The R Colored Vowel

There are certain vowels that are made by putting our vocal tract in the position to make the , but curling the tongue back slightly. This slight tongue curling makes the vowel sound somewhat rhotic, or "r-like", sound . This sound is found in words like fern.

Summary

Vowels are sounds that are made by vibrating our vocal cords and changing the structure of our vocal tract, which includes our lips, jaw, and tongue, in order to make a sound while not blocking the air flow. Vowels have a lot of energy when we say them. Vowels can occur by themselves, as monophthongs, as well as in the form of diphthongs, which are pairs of vowels that are said together and perceived as one vowel. The qualities generally used for of classifying vowels by qualities are height, backness, roundedness, and tenseness.