Stumbling syllables is a term used to describe the way a person speaks when they are having difficulty pronouncing words. UHS is an acronym for Unstressed-Head-Stressed, which is a type of syllable structure in English. This structure is characterized by an unstressed syllable followed by a stressed syllable, and then another unstressed syllable. Stumbling syllables occur when a person has difficulty pronouncing the stressed syllable, resulting in a stuttering or stammering sound.