A syllable is a single, unbroken sound of a spoken (or written) word. Syllables usually contain a vowel and accompanying consonants. Sometimes syllables are referred to as the ‘beats’ of spoken language.
Syllables differ from phonemes in that a phoneme is the smallest unit of sound; the number of syllables in a word is unrelated to the number of phonemes it contains. For example: /b/, /k/, /t/, /ch/, /sh/, /ee/, /ai/, /igh/, /ear/ are all phonemes. The word ‘chat’ is made up of three phonemes (/ch/ /a/ /t/). The word ‘light’ is made up of three phonemes (/l/ /igh/ /t/). However, both the words ‘chat’ and ‘light’ have only one syllable each.
The number of times you hear a vowel (a, e, i , o, u) in a word is equal to the number of syllables a word has. A good way to identify syllables is to think about whether you need to change your mouth shape to say the next bit of the word / the new syllable.