When we speak, there is more energy involved in producing some syllables than in others,
and when we listen to others speaking we recognise that some of the syllables are more
prominent than others. The syllables that we hear as prominent are stressed and contain full,
unreduced vowels, e.g. /e/, /i:/, /aʊ/, etc . On the other hand, the unstressed or weak syllables
usually contain weak vowels, which are, in decreasing order of frequency, schwa /ǝ/ , /i/, and
/ʊ/. Syllabic consonants are also considered weak (They are usually preceded by a dropped
schwa).