The glottal stop is a consonant sound produced when the flow of air is stopped by the glottis closing, and then released. Many languages use glottal stops, often much more than in English.
The sound /t/ in ‘cat' is often a glottal stop sound.
In the classroom
Few learners have difficulty producing the glottal stop sound but they can have problems understanding words that can be pronounced with it in certain accents, like bottle and butter. Listening to examples from speakers with relevant accents and following tapescripts identify different ways of pronouncing the same words.