SYLLABIC
Vowels usually constitute the "main core" or the nucleus of syllables; every vowel is at the center of a single syllable. Vowels can even occur as syllables. For instance, the word ago /əˈgəʊ/ is composed of two syllables: /ə/ and /gəʊ/. The first syllable is a single vowel. Even in the second syllable, the vowel (or the diphthong) takes the prominence (or stress) on itself. Therefore, vowels are said to be [+syllabic].
It was pointed out earlier that every language of the world contains the two basic classes of speech sounds often referred to by the cover terms consonants and vowels. This classification implies that consonants and vowels differ. In the production of consonants the flow of air is obstructed as it travels through the mouth. Vowels are produced with no obstruction in the mouth whatsoever. Oral and nasal stops, fricatives, affricates, liquids, and glides all have some degree of obstruction and are therefore consonants.
Consonants do not correspond exactly to the sounds specified as [+consonantal], because glides are [-consonantal], forming a subclass with vowels (which is why they often occur as part of a vocalic diphthong, and are also called semi-vowels). However, unlike vowels, glides are produced with some small oral obstruction and therefore do not constitute syllable peaks (i.e., they can neither occur as syllables nor do they govern stress), as do vowels. Vowels, like glides, are [-consonantal] and [+sonorant]. They differ from glides because they constitute syllable peaks; so vowels are [+syllabic], whereas glides are [-syllabic].
Liquids and nasals can also be syllabic—function as a syllable. Liquids and nasals are not always syllabic; rather, they can be syllabic. That is:
They may constitute separate syllables, as shown by the words Rachel [reɪʧļ], faker [feɪkŗ], rhythm [rɪðm̩], and button [bʌtņ]. These words could also be pronounced as /ˈreɪʧəl/, /ˈfeɪkər/, /ˈrɪðəm/, and /ˈbʌtən/.
They may be nonsyllabic, as in the words lead /li:d/, read /ri:d/, deal /di:l/, name /neɪm/, or mean /mi:n/.
Similarly, the vowel sound in words like bird and verb are sometimes written as a syllabic /r/ (i.e., [bŗd] and [vŗb]); most dictionaries, however, prefer to transcribe syllabic vowels as /ə/ (e.g., [bərd], [vərb]). This is the only instance where a schwa represents a stressed vowel. The diacritic symbol [ ˌ] usually appears under the phoneme to represent its [+syllabic] feature.
By the system shown in Table 4.3, obstruents and vowels are distinct classes; they do not share any feature. Glides are like consonants in the sense that they are in the class of [-syllabic] sounds, but they are like vowels in the sense that they are [-consonantal] and [+sonorant]. Similarly, liquids and nasals are in the [+consonantal] class with obstruents, but share the feature [+sonorant] with vowels (and sometimes are [+syllabic]). Nonsyllabic liquids, nasals, and glides (or semivowels) are in the class of [+sonorant, -syllabic] sounds.
The syllabicity of liquids and nasal consonants may also be shown by describing the words in which they function as syllables as having short vowels before the liquids. So, whenever a short vowel precedes a liquid or a nasal consonant, the nasal consonant or the liquid becomes [+syllabic].
In many English dictionaries, short vowels that occur before syllabic phonemes are placed within parentheses to indicate that they are optional. Take the following examples:
In these cases, the schwa can be deleted due to the syllabicity of the phonemes that follow it. As it was mentioned earlier, this is the only instance where a schwa represents a stressed vowel.
