As a result of the obstruction of the airflow in the glottis, the glottal vibration either stops or becomes irregular with a low rate and sudden drop in intensity.
In many Polynesian languages that use the Latin alphabet, however, the glottal stop is written with a rotated apostrophe, ⟨ʻ⟩ (called ʻokina in Hawaiian and Samoan), which is commonly used to transcribe the Arabic ayin as well (also ⟨ʽ⟩) and is the source of the IPA character for the voiced pharyngeal fricative ⟨ʕ⟩.
In most cases, however, a word that begins with a vowel-letter (e.g. Tagalog aso, "dog") is always pronounced with an unrepresented glottal stop before that vowel (as in Modern German and Hausa).
Some orthographies use a hyphen instead of the reverse apostrophe if the glottal stop occurs in the middle of the word (e.g. Tagalog pag-ibig, "love"; or Visayan gabi-i, "night").
SENĆOŦEN – whose alphabet is mostly unique from other Salish languages – contrastly uses the comma ⟨,⟩ to represent the glottal stop, though it is optional.
[citation needed] In the Nawdm language of Ghana, the glottal stop is written ɦ, capital Ĥ.
In English, the glottal stop occurs as an open juncture (for example, between the vowel sounds in uh-oh!,[9]) and allophonically in t-glottalization.
[clarification needed][15][14][16] In many languages that do not allow a sequence of vowels, such as Persian, the glottal stop may be used epenthetically to prevent such a hiatus.
There are intricate interactions between falling tone and the glottal stop in the histories of such languages as Danish (see stød), Cantonese and Thai.
[citation needed] In some languages that normally maintain the flow of vowels fluid, a glottal stop can be added exceptionally for emphatic reasons in particular circumstances.