A syllable is a unit in a sequence of sounds made when speaking. For example, in the word dog we have one syllable, dog. Dog is a monosyllable. It is a monosyllabic word.
Other words with two syllables are disyllabic like the word English. En.glish
Trisyllabic words have three syllables. Syllable is a trisyllabic word. Sy.lla.ble
Polysyllabic words have more than three syllables, but polysyllabic can also refer to any word with more than one syllable. Polysyllabic is a polysyllabic word. It has five syllables. Po.ly.sy.lla.bic
You can see that all syllables contain a vowel sound supported by consonants.
Most syllables have an onset which consists of one or more consonants. English allows some multi-consonant onsets. Your language may not.
The onset is followed by the nucleus. The nucleus is normally made up of the vowel, and the nucleus forms the peak of the syllable.
The smallest possible syllable consists only of the nucleus. The monosyllabic words eye and ear both have only a nucleus.
The nucleus can be followed by a coda – this literally means tail. A nucleus that is not followed by a coda is called an open or free syllable.
A nucleus that is followed by a coda is called a closed or checked syllable.
English allows both closed and open syllables.
Though most syllables contain a vowel as their nucleus, the vowel may be a monophthong or a diphthong.