Glottalization

Full definition of glottalization

(countable and uncountable; plural glottalizations)

(linguistics) The act or process of constricting or closing the glottis during the production of a speech sound that normally does not involve such constriction.Examples of glottalization include creaky voice, and the interrupted tones of Vietnamese.
(linguistics) Transformation of a consonant into a glottal stop or fricative.