Glottal Stop [ʔ]
The glottal stop is a voiceless plosive consonant sound, made by stopping air in the throat (glottis) as it leaves the body. In English pronunciation, the glottal stop is frequently used as an allophone of /t/ in connected speech:
Glottal Stop Usage
The glottal stop is most often heard replacing a syllable-final /t/ before another consonant sound:
This also occurs in connected speech where a word ends with /t/ and the next one begins with a consonant sound:
I can’t see.