Vowel shortening

We have seen elsewhere (see Table 1 Simple Vowels Summary) that English monophthongs can be categorized according to duration. We noted that there are seven short vowels and five long vowels. To the group of long vowels we can also add all the diphthongs, as these are all generally longer in duration than the short vowels. These groupings are summarized again in Table 2.

Table 2. English vowels categorized by duration.

The difference between short and long monophthongs can be highlighted by examining some minimal pairs:

bid /bɪd/ ― bead /bid/
bed /bɛd/ ― bird /bɜd/
bad /bæd/ ― barred /bɑd/
bud /bʌd/ ― bored /bɔd/
pot /bɒd/ ― booed /bud/

By saying these pairs of words aloud, the difference in duration between the words with short vowels (left column) and their complementary long vowel words (right column) is quite apparent. The IPA symbol used to mark long duration is [ː]. The long-vowel words in the right-hand column in the list above would, therefore, be transcribed phonetically as:

bead [biːd]
bird [bɜːd]
barred [bɑːd]
bored [bɔːd]
booed [buːd]

Now, consider what happens to the long vowel in each of these words when they are matched with a different partner:

bead /bid/ ― beat /bit/
bird /bɜd/ ― Bert /bɜt/
barred /bɑd/ ― Bart /bɑt/
bored /bɔd/ ― bought /bɔt/
booed /bud/ ― boot /but/

Once more, you will be better able to appreciate any difference by saying each pair of words aloud. By doing so, you should notice that even though the same long-vowel phoneme appears in each pairing, the vowel in the right-hand column words is shortened. For example, the /i/ in bead /bid/ is longer than the /i/ in bit /bit/, and the /ɔ/ in bored /bɔd/ is longer than the /ɔ/ in bought /bɔt/. The only difference in the environments of these minimal pairs is the voicing of the final consonant. The left-hand column of words has the voiced alveolar plosive /d/ in final position and the right-hand column words all end with the voiceless alveolar plosive /t/. What we find, in fact, is that whenever a long-duration vowel (long monophthong or a diphthong) occurs before a voiceless plosive, fricative or affricate, the vowel is shortened. The shortened vowels are represented phonetically without the lengthening symbol [ː]. We see, therefore, that each long-duration vowel has at least two allophones: a shortened form before voiceless plosives, fricatives and affricates, and a non-shortened form that appears elsewhere. Transcribing the above list of words both phonemically and phonetically should make this clear:

bead /bid/ ― beat /bit/
bird /bɜd/ ― Bert /bɜt/
barred /bɑd/ ―Bart /bɑt/
bored /bɔd/ ― bought /bɔt/
booed /bud/ ― boot /but/

We can say, therefore, that the phoneme /i/ has at least two allophones [i] and [iː], the phoneme /ɜ/ has at least two allophones [ɜ] and [ɜː], and so on. [NB: The short vowels do not have any variants with respect to this feature of shortening.] Table 3 shows all the shortened vowel allophones in English.

Table 3. Shortened vowel allophones.

NEXT>> Nasalization