To study the syllable as a phonological unit of English is to describe the structure of the syllable by stating the functions of the phonemes in it and the relations between the phonemes.
Syllable formation in English, as in other languages, is based on the phonological opposition of vowels and consonants. Vowels are always syllabic, they occupy a central position in the syllable. Consonants are non-syllabic and marginal. The sounds /w, r, j/, despite their strong vocalic features, function as consonants, occurring only before the vowel, e.g. /ˈwɪn—tǝ/, /'ri:—dǝ/, /jɑ:d/. The sounds /I, m, n/ normally function as consonants, in various sound combinations before the vowel. But in unstressed final position, when preceded by a noise consonant, they are syllabic, e.g. /petl/ "petal", /blɒsm/ "blossom',' /laɪtn/ "lighten".
It should be noted specially, that historically short English vowels /ɪ, e, æ, ʌ, ɒ, ʊ, ǝ/ never occur in stressed final position without the following consonant. In unstressed position the vowels /ɪ, ǝ/ ñàn occur as final.
Consonants present particular interest in the study of the syllable, because it is due to the number and arrangement of consonants that the structure of the syllable varies. And it is largely due to consonants that we understand the utterance.
As to the presence, number and arrangement of consonants there are 23 syllable patterns in English, such as V, VC, CVC, CV, CCVC, CCVCC, CCCVC, CCCVCC, etc. The vowel may occur alone in a syllable or it may have up to 3 consonants before it and up to 4 consonants after it. The most frequent and fundamental pattern in English is CVC.
It is a feature of English that in initial position, i.e. before the vowel, there can be any consonant except /ŋ/; no consonant combinations are possible with /ð, z/, and such consonant clusters as /mh, sr, spw, fs, hr, stl/ cannot occur initially either.
J. O'Connor notes that final clusters are much more complex in English than initial ones. This is due to the fact that final clusters are used to express grammatical meanings of plurality, tense, ordinal number, e.g. "texts" /-ksts/, "mixed" /-kst/, "glimpsed"/—-mpst/. In Russian initial clusters are more complex and more numerous than the final ones, because they represent grammatical prefixes, e.g. /fskr-, fspl-, vzr-, kst-/.
Phonotactic possibilities of English phonemes predetermine the rules of syllable division.
English historically short vowels under stress (checked vowels) occur only in a closed syllable. Checked vowels are always followed by a consonant. So the syllabic boundary never occurs after these vowels.
The preceding and following vowels attract this consonant and the consonant is split into two. In speech the consonant forms a close link between the two syllables. If a checked vowel is separated by one consonant from a syllabic sonant the boundary between the two syllables is also within the consonant. E.g. ˈlɪtl, ˈkɒtn, ˈfætn,'bɪtn.
Historically long monophthongs, diphthongs and unstressed short monophthongs (free vowels) can occur both in the open and in the closed syllable. E.g. /kɑ:/ "car", /kɑ:t/ "cart", /taɪ—nil "tiny".
When a free vowel is separated from a succeeding vowel by only one consonant sound, the syllable in which such a vowel occurs, is always open. E.g. /aɪ—ˈdɪǝ/ "idea", /kɑ:—ˈtu:n/ "cartoon".
When a post-stressed short vowel is separated from a succeeding vowel by a single consonant, the boundary is most probably, before the consonant, because the short vowel is free in unstressed position.
When there is a cluster of consonants between two vowels, the place of the syllabic boundary is conditioned by whether this cluster is permitted at the beginning of words or not. If it does occur in initial position in English the syllabic boundary is before it. If it doesn't, the boundary is between the consonants. For instance the cluster /gr/ is used word—initially in English, therefore it can occur at the beginning of a syllable and the syllabic boundary is before the cluster. E.g. /ǝ—ˈgri:/ "agree", /rɪ—ˈgret/ "regret".
The clusters /dm/, /dv/ do not occur word-initially and cannot occur at the beginning of a syllable. The syllabic boundary is therefore between the consonants constituting the clusters. E.g. /ǝd—'maɪǝ/ "admire", /ed-ˈvaɪs/ "advice”.
When two vowels are separated by more than two consonants as for example in /ˈekstrə/ the boundary may be both before /s/ and /t/ because both /str/ and /tr/ occur at the beginning of words and /ks/ can occur in final position.
The so-called triphthongs in English are disyllabic combinations, because they contain two vowel phonemes. E.g. /ˈsaɪ—əns/ "science", lˈflaʊ - ǝ/ "flower".
The structure of an English syllable depends on whether it is stressed or not. The peak of the stressed syllable is always a vowel. In the unstressed syllable the peak may be a vowel or a sonant. When the peak of the stressed syllable is a short vowel, the syllable must be "closed" by a consonant.