Vowels of General American English
Listen to the vowels in the words bit, bet, bat, but beat, bait, boot, boat, bought, bite, and bout. At least how many distinct vowels does English have?
The first thing to note about the English vowels is that they are a great deal more complicated than the Spanish or Japanese vowels. This complexity has several consequences. First, there is considerable disagreement among linguists on the details of how to describe English vowels, and even some of the brief comments I have to make about them below may be disputed by one or another linguist. Second, there are considerable differences between dialects, and this makes an overall description of English vowels difficult, if not impossible. Third, the English vowel system (within a given dialect) is not as stable as a simpler system like that of Spanish, and it is more likely to change over time.
In this section, we will consider only the vowels of General American English (GA), specifically the variety that I speak. (If you are not a speaker of GA, some of your vowels may differ from those we'll be describing. Many of these differences are described in the section on English accents.) Let's begin with the front vowels. These are the vowels in the following words, each followed by the symbol I will use to represent the vowel: beat (/i/), bit (/ɪ/), bait (/e/), bet (/ɛ/), bat (/æ/). The approximate positions of these vowels in vowel space are shown in the figure below. Again you can click on a symbol to hear the vowel.
You can see that five vowels are squeezed into the front part of the vowel space, the same number of vowels that Spanish has all together. If the differences in height (and minor differences in backness) were the only dimensions distinguishing these vowels, this would put quite a burden on the hearer, who after all has to figure out that beat and bit are different words. It would also be a burden on the speaker, who would have to be very careful in placing the tongue for each vowel.
How English "Long" and "Short" Vowels Differ
So not surprisingly, these vowels are also distinguished from each other along other dimensions. We can put the highest four vowels in two groups, one consisting of the those traditionally called "long", /i/ and /e/, the other consisting of those traditionally called "short", /ɪ/ and /ɛ/. (The fifth vowel, /æ/, tends to group with the "short" vowels.) There are at least three differences between these two groups. First, the "long" vowels really do tend to be longer than the short vowels. Second, the "short" vowels tend to be "pure"; that is, the position of the tongue does not change during the production of the vowels. The "long" vowels, on the other hand, involve some movement, in both cases toward the upper left corner of vowel space. This is more noticeable for /e/ than it is for /i/ (but in other dialects, it is quite striking for /i/ too). Third, though you probably can't feel this yourself, for the "long" vowels, the base ("root") of the tongue is pushed forward. Finally, the muscles in the tongue are tenser than for the short vowels. Because values on the last two dimensions tend to go together, they are often considered to be a single dimension called tenseness. The two extremes on this dimension are referred to as "tense" and "lax".
So we again have redundancy, as many as five different dimensions distinguishing /i/ from /ɪ/ and /e/ from /ɛ/. It appears that speakers do not always make use of all of these dimensions to achieve the differences that hearers hear in them.
Now let's look at the central and back vowels phonemes of GA. These are the vowels in the following words, with the symbols for each after them: boot (/u/), put (/ʊ/), boat (/o/), bought (/ɔ/), pot (/ɑ/), but (/ʌ/). (Note: many GA speakers do not make a distinction between /ɔ/ and /ɑ/; more on this in the section on English accents.)
English Vowels are So Complicated that Linguists Don't Agree on How to Treat Some of Them.
There is an additional central vowel, symbolized by /ə/, that appears in two quite distinct environments. (The IPA symbol for this sound is an upside-down e.) First, it is the most common vowel in unstressed syllables in English, that is, syllables that are weakly articulated. An example is the first phone in the word about and the last phone in the word comma. Some people consider this to be the same phoneme as /ʌ/; the main reason for treating it separately is that it behaves differently from /ʌ/ in the history of the language as well as in a number of modern dialects. Second, it appears followed by the consonant /r/ (in stressed and unstressed syllables). This combination is worth mentioning because speakers normally combine the two phones into one vowel sound. Examples are the beginning of the word earth and the end of the word actor. Again there is disagreement about how to treat the phone; some people would prefer to treat /ər/ as a single phoneme in the language.
The approximate positions of the back and central vowels in vowel space are shown in the figure below. Again you can click on a symbol to hear the vowel.
Again we find a large number of vowels squeezed into a region of the height-backness space, and, not surprisingly, the vowels differ on other dimensions. Like /i/ and /e/, /u/ and /o/ belong to the set of "long" vowels. Both share the features of the other long vowels: length, tendency to "move" as they are pronounced, and tenseness. /ʊ/, /ɑ/, and /ʌ/ are clearly "short" vowels, sharing features with the front "short" vowels /ɪ/, /ɛ/, and /æ/. /ə/ is "short" in its unstressed form, but in the /ər/ combination, it resembles the "long" vowels. /ɔ/ can also be relatively long, although it is usually lax, so it doesn't fit neatly into the division between "long" and "short" vowels.
How Two Vowels Can Behave like One
There are three other "long" English vowels, all of them involving significant movement during their production. Vowels of this sort, in which the position of the tongue changes a lot during their production, are called diphthongs. The symbols for diphthongs indicate both the beginning and the end positions. Diphthongs are different from pairs of vowels in that one of the two parts is pronounced more forcefully than the other; for these English diphthongs the more forceful part is the first. The English diphthongs are exemplified in the words bite, bout, and boy; they are represented by the symbols /ay/, /aw/, and /ɔy/. (Note that the symbol at the beginning of the first two has not been used elsewhere for English, though it was used for Spanish and Japanese. It represents a low vowel that is further front than /ɑ/; we'll meet it again later when we discuss English accents.) The symbols [y] and [w] are used for the second members of the diphthongs; these correspond closely to the vowels [ɪ] and [ʊ]. We will meet these symbols again inthe section on English consonants. The use of these consonant symbols helps to show that the part of the diphthong that is "stronger" is the first element. The figure below shows the paths that each of the diphthongs traces in vowel space. You can click on the beginning symbol to hear the vowel it represents.
You may be wondering why the diphthongs /ay/, /aw/, and /ɔy/ are considered individual phonemes when each seems to consist of more than one phone. Why can't we just treat them as sequences of two vowel phonemes? The main reason is that the initial elements of these diphthongs behave quite differently from any of the simple vowels. As we'll see later when talk about differences between English accents and phonological change, the pronunciation of these diphthongs in a particular dialect and at a particular point in the history of the language seems to have nothing directly to do with the pronunciation of any of the simple vowels. For example, changes in /æ/ and /ɑ/ over time may be unrelated to changes in /ay/ and /aw/. Thus these diphthongs appear to be inseparable units for English speakers and hearers.
General American has one more diphthong that is not usually considered to be an individual phoneme. This is the part of the word few following the initial "f" sound. Unlike the three diphthongs discussed above, in this one it is the second element that is "stronger". I will write this diphthong as /yu/. In modern English we can treat /yu/ as two separate phonemes because the second element tends to behave like the vowel /u/ in most dialects; when /u/ changes its pronunciation over time, /yu/ changes as well. The /y/ also appears to be a separate element in that its pattern of occurrence depends on the consonant that precedes it. Consider the following words: resume, lewd, news, Tuesday, few, beautiful, music, cute. In some accents, all of these words have /yu/; in others, /yu/ is used in the last six; in others (for example, GA), /yu/ is used only in the last four; in others, /yu/ never occurs.
Note that we have already discussed six dimensions for describing vowels: height, backness, length, rounding, tenseness, and whether the vowel height and backness change during the production of the vowel. I'll call this last dimension diphthongization. For GA, all we need to specify for this dimension is whether there is movement in the direction of a high front position ([i]), in the direction of a high back position ([u]), or not at all. (There are other possibilities in other English dialects, as we will see later.) Now we can describe all of the English vowels in terms of their values on these dimensions. The table below does this (for all of the dimensions except length). The point here is not to memorize any of this — there is, after all, considerable disagreement about the details — the point is to see how articulatory dimensions (features) allow us to begin to capture what speakers and listeners seem to know about the vowel phonemes of a language.
|Height||hi||hi||hi mid||low mid||low|
|Height||hi||hi||hi mid||low mid||low||hi mid||low mid|
|Height||low → hi||low → hi||mid→hi|
|Backness||center → front||center → back||back → front|
|Rounding||∅||∅ → round||round → ∅|
Here are examples of each vowel, again as pronounced in my accent. You may notice that the vowels do not sound exactly the same in different words. Since each phoneme is a category, we should expect there to be different variants in the same way that not all apples look alike. I'll have more to say about this variation within phonemes in the section on phonetic contexts.
|/i/||bead, need, happy|
|/ɪ/||bid, near, insist|
|/ɛ/||bed, head, berry|
|/æ/||bad, ban, bat|
|/u/||booed, new, tune|
|/ʊ/||book, put, poor|
|/o/||boat, wrote, old|
|/ɔ/||bought, saw, lost, born|
|/ɑ/||body, father, bar|
|/ə/||about, sofa, further, listen, convince|
|/ay/||ride, write, buy|