Let us now look in more detail at syllable onsets. If the first syllable of the word in question begins with a vowel (any vowel may occur, though ʊ is rare) we say that this initial syllable has a zero onset. If the syllable begins with one consonant, that initial consonant may be any consonant phoneme except ŋ; Ʒ is rare.

We now look at syllables beginning with two consonants. When we have two or more consonants together we call them a consonant cluster. Initial two-consonant clusters are of two sorts in English. One sort is composed of s followed by one of a small set of consonants; examples of such clusters are found in words such as 'sting' stɪŋ, 'sway' sweɪ, 'smoke' sməʊk. The s in these clusters is called the pre-initial consonant and the other consonant (t, w, m in the above examples) the initial consonant. These clusters are shown in Table 2.

The other sort begins with one of a set of about fifteen consonants, followed by one of the set l, r, w, j as in, for example, 'play' pleɪ, 'try' traɪ, 'quick' kwɪk, 'few' fju:. We call the first consonant of these clusters the initial consonant and the second the post-initial. There are some restrictions on which consonants can occur together. This can best be shown in table form, as in Table 3. When we look at three-consonant clusters we can recognize a clear relationship between them and the two sorts of two-consonant cluster described above; examples of three consonant initial clusters are: 'split' split, 'stream' stri:m, 'square' skweə. The s is the pre-initial consonant, the p, t, k that follow s in the three example words are the initial consonant and the l, r, w are post-initial. In fact, the number of possible initial three-consonant clusters is quite small and they can be set out in full (words given in spelling form):

Note: Two-consonant clusters of s plus l, w, j are also possible (e.g. slɪp, swɪŋ, sju:), and even perhaps sr in 'syringe' srɪnʤ for many speakers. These clusters can be analyzed either as pre-initial s plus initial l, w, j, r or initial s plus post-initial l, w, j, r. There is no clear answer to the question of which analysis is better; here they are treated in the latter way, and appear in Table 3.

Table 3 Two-consonant clusters with post-initial l, r, w, j