Functions of glottal stop
1. Used as a way of adding emphasis to a syllable that begins with a vowel sound
2. Used to separate adjacent vowel sounds in successive syllables
3. Used as an allophone of the phoneme /t/ in certain positions (glottalling or glottal replacement)
4. At the end of a syllable, especially before a consonant, can make certain sounds (/p/, /t/, /tʃ/,/tr/, /k/) stronger (glottal reinforcement)