|Writing system||Latin script|
|Language of origin||Unified Northern Alphabet|
Heng ('? ?') is primarily used in modern Latin alphabets for various Indigenous Languages of the Caucasus to represent the glottal stop [?]. Additionally, the digraphs '?u ?u', '?ý ?ý', and ' ' are used in some of the languages to represent , , and  respectively.
'? ?' is used some modern Latin typography for nearly all of the Northeast Caucasian and Northwest Caucasian languages (aside from Abkhaz), as well as Mingrelian and Svan of the Kartvelian family. '?u ?u' is used in some Latin transcriptions of Adyghe and Kabardian of the Northwest Caucasian family, '?ý ?ý' is used only in the Abzakh dialect of Adyghe, and ' ' is used in phonologically precise Latin transcriptions to show the more common realisation of the epiglottal stop in Chechen of the Northeast Caucasian family (which is written '? ?' when realised as an actual epiglottal stop).
It is sometimes used to write Judeo-Tat.
It has been occasionally used by phonologists to represent a hypothetical phoneme in English, which includes both [h] and [?] as its allophones, to illustrate the limited usefulness of minimal pairs to distinguish phonemes. Normally /h/ and /?/ are considered separate phonemes in English, even though a minimal pair for them cannot be constructed, due to their complementary distribution.
Both Ꜧ LATIN CAPITAL LETTER HENG (HTML
Ꜧ) and ꜧ LATIN SMALL LETTER HENG (HTML
ꜧ) are encoded in Unicode block Latin Extended-D.
A variant form, ɧ LATIN SMALL LETTER HENG WITH HOOK, is encoded as part of the IPA Extensions Block. It is used to represent the voiceless palatal-velar fricative in the International Phonetic Alphabet.
It represents using the shha with a hook