Initially strong consonants, in the articulation of which the beginning is stronger while the end is weaker. They occur at the end of a closed syllable.
E.g. ɪt, ʌs, pɪn, sæd, pɑ:t
Finally strong consonants, in the articulation of which the beginning is weak while the end is more energetic. They occur at the beginning of a syllable.
E.g. mi:, taɪ, pɑ:t, sæd
Double-peaked consonants, in the articulation of which both the beginning and the end are energetic whereas the middle is weak. Acoustically they produce the impression of two consonants. These consonants occur at the junction of words or morphemes.
E.g. pennaɪf, ðættaɪm, mɪddeɪ.
The type of consonant is therefore a cue for syllable division. If in /ǝ naɪs haʊs/ the sound /n/ is initially strong, the syllabic boundary is after the /n/ — /ǝn aɪs haʊs/. If the sound /n/ is finally strong, the boundary is before it— /ǝ naɪs haʊs/. In other words, if there is a new onset of muscular tension on the sound /n/, the latter belongs to the second syllable, and if the new onset of muscular tension is on /aɪ/ ,the sound /n/ belongs to the first syllable.
The above theories define the syllable on either the production or perception level.
N. Zhinkin has worked out the so-called loudness theory, which takes into account both the levels. On the perception level the syllable is defined as an arc of actual loudness. The experiments carried out by N. Zhinkin, showed that the organ immediately responsible for the variations in loudness of a syllable is the pharynx. The narrowing of the pharyngeal passage and the resulting increase in muscular tension of its walls reinforce the actual loudness of the vowel thus forming the peak of the syllable, while the loudness of the marginal consonants is weakened. In the production of loudness variations of all the speech mechanisms are involved. So on the speech production level the correlate of "the arc of loudness" is "the arc of articulatory effort".
The acoustic aspect of the syllable has been studied by E. Zwirner, R. Jakobson and M. Halle. According to the results obtained, the peak of the syllable (a vowel or a sonant) has a higher intensity than its consonants, and in many cases a higher fundamental frequency. Perceptually, the peak is louder and higher in pitch. These acoustic features easily agree with the physiological definition of the syllable as an arc of articulatory effort (or muscular tension), In analysing the above theories of the syllable, we cannot but agree with the scholars who point out that each of the existing theories is correct to a certain extent, but none of them is able to explain reliably all the cases of syllable boundaries.
It seems that the phonetic definition of the syllable should also take into account the peculiarities of the articulatory basis of a concrete language, the characteristic tendencies in articulatory transitions from a consonant to a vowel (CV transition), from a vowel to a consonant (VC transition) and from a consonant to a consonant (CC transition).
In English CV transitions are loose, and, therefore the voiceless plosives /p, t, k/ before stressed vowels are aspirated. So the presence of aspiration can indicate that the consonant and the vowel belong to the same syllable, e.g. /plʌmpaɪ/.The absence of aspiration shows that they belong to different syllables, i.e. there is a syllable boundary after the consonant, e.g. in "plump eye" /plʌmpaɪ/.
VC transitions are often close in English, because of the checked character of short vowels under stress. Such a VC combination forms one syllable. In unstressed position a short English vowel is not checked and because of the loose VC transition it may form one syllable and the following consonant may belong to another one, e.g. "positive" /ˈpɒz-ɪ-tɪv/.