As we have seen, “vowel” is a manner of articulation. Accordingly, there are no manner distinctions in vowels. As for places of articulation, vowels may be labelled palatal or velar. Actually, front and back, respectively, are more common terms used for these two categories in vowels. Labiality in vowels is referred to as rounded. However, the most important property of vowels is tongue height or the openness of the mouth.
Vowels may be distinguished by how open the mouth is during their pronunciation. The
The close/high vowels The shape of the lips is also different in these two vowels:
while front vowels are pronounced with spread lips. This is a universal markedness tendency: any human language is expected to have liprounding for front vowels only if that language also has unrounded front vowels, and vice versa, unrounded back vowels are only expected to occur in languages that have rounded back vowels too.
So some languages have only front unrounded vowels, others have these
Vowels may not only be either high or low, some vowels are between these two edges. Languages differ in whether they have one or two (some even three) vowels between the highest and the lowest vowel. For a start, the IPA provides two symbols between
The same four-step scale is posited for back vowels, giving us four more cardinal vowels, #5:
In spite of this, as we are going to see soon, the IPA provides symbols for rounded low vowels too. The other notable thing is the difference between
The positions in these diagrams were taken from x-ray photos. The first such photos from 1917 are shown here. The black dots are the image of a lead chain the person in the photos has half swallowed for the sake of the experiment. This shows clearly the shape of their tongue. The red dots indicate the highest point of their tongue.
The eight cardinal vowels are shown in this chart together with their conventional numbers. The arrangement you see here is called Jones vowel chart after Daniel Jones, who had x-ray photos made of his head while pronouncing different vowels. (Yes, you have just seen his skull and jaw!)
We have seen that it is not only along the high–low and the front–back scales that vowels vary, but liprounding may also be distictive in them. The rounded counterpart of As you may already suspect, each cardinal vowel has a counterpart which is rounded for the front vowels and
You may recall that we said some languages distinguish as many as five vowel heights. To be able to transcribe so many vowels, the IPA provides a further symbol between
Furthermore, similarly to the nonhigh nonlow vowels, there are vowels that are neither front, nor back. These are called central. The best-known central vowel is in the middle of the vowel chart, and is called schwa:
Finally here is the Jones vowel chart with all the vowels we have talked about so far, and some more central vowels.
You can listen to samples of these vowels here.
Phonologists often make a distinction between tense and lax vowels. These terms refer to the tenseness vs relaxed state of the muscles while pronouncing the relevant vowels. Compare the short
The following chart contains some tense/lax pairs. Comparing them with the Jones vowel chart above, you can see that tense vowels are always a bit closer than their lax counterpart. One cannot generally say that tense vowels are closer than lax ones, since lax
tense | ||||
---|---|---|---|---|
lax |
Since it leads to a somewhat different result, we will briefly describe an acoustic analysis of the vowel space too.
In acoustic terms vowels are described by their formants. Without going into too much detail here, we may say that a complex sound — like a vowel — is made up of a series of resonances at various frequencies. These frequencies can be shown on a spectrogram, like the one below. There are frequency ranges where resonances gather in different vowels, these are their formants. These are the darker grey areas, labelled as “F1” and “F2” in red in the spectrogram below.
The lowest frequency range is called the first formant (F1), the second lowest the second formant (F2), and so forth. The first formant of high vowels is lower than the first formant of low vowels. The second formant of front vowels is higher than the second formant of back vowels, or at least the first two formants are further apart in front vowels than in back vowels.
low F1 = high vowel, high F1 = low vowel
low F2 = back vowel, high F2 = front vowel
Lip rounding modifies the relationship of F2 and F3, r-colouring (see below) is a result of lowered F3, but this much will suffice for us.
The Jones vowel chart shown above is organized by the articulatory properties of vowels. However, based on their formants of the same vowels, another, quite similar chart can be produced, this is shown below.
In this chart there is a single low vowel,
We have seen that vowels may be high or low (or somewhere in between), they may be front or back (or in between), and they may be rounded or unrounded (which strongly correlates with their being front or back). There are some further categories in which two vowels can be different
During the default pronunciation of a vowel, the velum is raised and air does not escape through the nose. If the velum is lowered and air does go through the nose too, the result is a nasalized vowel. The IPA marks this by a tilde diacritic above the vowel symbol, eg
Another possible modification to vowels is retroflexivization, ie curling the tongue back, during the pronunciation of the vowel. The vowel so pronounced is said to be r-coloured or retroflex or rhotic. This is not a very common way of pronouncing vowels, we mention it though because some accents of English, the best-known of which is General American,
Vowels may also be distinct in their length relative to each other. Vowel length is often accompanied by other differences: English hat
A diphthong is a vowel that changes its quality from beginning to end. Diphthongs are usually transcribed by two vowel symbols, the first representing the starting point of the diphthong, the second its ending point. For example, the word eye could be transcribed
Depending on the relationship of the two halves of a diphthong, we can distinguish closing and opening diphthongs. In a closing diphthong the end half is a close vowel, in an opening diphthong it is an open vowel. There also are centring diphthongs, these end in the central vowel,
Either the beginning or the end of a diphthong is syllabic: it constitutes the centre of the syllable. If the first part is syllabic, we talk about a falling diphthong — like
The nonsyllabic part of a diphthong is called an offglide (in falling diphthongs) or an onglide (in rising diphthongs). It is very difficult to tell if an offglide or an onglide is a vowel or a consonant (a glide, recall, we labelled
vowel | nonsyll vowel | consonant | |
---|---|---|---|
cow | |||
wax | ( | ||
say | |||
yes | ( |
The British tradition is to transcribe offglides as vowels, and onglides as consonants (