A syllable is a unit of pronunciation with one vowel sound. Some words have just one syllable, while others are made up of multiple syllables. Unlike a morpheme, a syllable does not have to make meaning. For example: The word “responsible” has four syllables (re-spon-si-ble). However, the word “hat” has only one syllable. While “understanding” has four syllables (un-der-stand-ing), it has two morphemes (understand-ing); “happy” is a two syllable word (hap-py) but has one morpheme.