Harsh voice, also called ventricular voice or (in some high-tone registers) pressed voice, is the production of speech sounds (typically vowels) with a constricted laryngeal cavity, which generally involves epiglottal co-articulation. Harsh voice includes the use of the ventricular folds (the false vocal cords) to damp the glottis in a way similar to what happens when a person talks while lifting a heavy load, or, if the sound is voiceless, like clearing one's throat. It contrasts with faucalized voice, which involves the expansion of the larynx.
When the epiglottal co-articulation becomes a trill, the vowels are called strident.
There is no symbol for harsh voice in the IPA. Diacritics seen in the literature include the under-tilde used for creaky voice, which may be appropriate when ambiguity is not a problem, the double under-tilde used as the ad hoc diacritic for strident vowels, which may be allophonic with harsh voice, and an ad hoc underline. In the Extensions to the IPA, the symbol is !, as in [a!], but this is ambiguous with the release of alveolar click.
The Bai language has both harsh ("pressed") and strident vowels as part of its register system, but they are not contrastive.
The Bor dialect of Dinka has contrastive modal, breathy, faucalized, and harsh voice in its vowels, as well as three tones. The ad hoc diacritics employed in the literature are a subscript double quotation mark for faucalized voice, [a͈], and underlining for harsh voice, [a̱]. Examples are,
^John Esling (2010) "Phonetic Notation", in Hardcastle, Laver & Gibbon (eds) The Handbook of Phonetic Sciences, 2nd ed.
Edmondson, Jerold A.; John H. Esling (2005). "The valves of the throat and their functioning in tone, vocal register, and stress: laryngoscopic case studies". Phonology (Cambridge University Press) 23 (2): 157–191. doi:10.1017/S095267570600087X.