Unusual airstream mechanisms
Clickshave already been discussed:
Ejectives (p’, t’, k’ etc.) are consonants pronounced in the following way: an oral closure is made as for an ordinary stop; at the same time the vocal folds close the glottis as when a glottal stop is pronounced. The larynx is pushed upwards with the glottis closed, compressing air in the vocal tract between the two closures. The oral closure is then released and there is a high-amplitude stop burst; finally, the glottal closure is released as well. Ejectives are pretty common sounds. According to Ladefoged & Maddieson they occur in about 18% of phoneme inventories. Ejective stops are often accompanied by affricates (ʦ’, ʧ’, tɬ’ etc.).
As full glottal closure precludes voicing, a voiced ejective would be a contradiction in terms. To be sure, there exists an extremely rare articulation known as ‘pre-voiced ejective’, symbolised dt’ etc. This is in fact a sequence beginning with a brief voiced stop terminated by a glottal closure; the final part is a regular voiceless ejective.
Ejectives should be distinguished from glottalised sounds produced with the ordinary pulmonic airstream mechanism, e.g.preglottalised stops (ʔp, ʔt, ʔd etc.). These are complex articulations consisting of a glottal stop and a plain oral stop partly overlapping each other in time. The oral stop is released in the ordinary manner and there is no characteristic ejective ‘pop’. Speakers of British English commonly preglottalise word-final or preconsonantal voiceless stops and affricates (e.g. mæʔʧ for ‘match’). This in turn should be distinguished from full ‘glottaling’, i.e. the replacement of a consonant (especially t) with a glottal stop.
Implosives (ɓ, ɗ, ɠ etc.) are considerably rarer than ejectives (about 10% of the world’s languages contain them) and more restricted geographically, occurring mainly in West Africa and Central America. An implosive requires an oral closure; the larynx is then lowered, generating a sufficient airflow through the glottis to make the vocal folds vibrate. If the movement of the larynx is very fast, there is a negative pressure in the oral cavity, so that air rushes into the mouth on the release of the oral closure with a characteristic implosive burst. However, if the larynx is lowered slowly, the glottal airflow equalises air pressure and there is no audible burst. Implosives may also be pronounced with the glottis fully closed, so that they remain voiceless through most of their articulation (these very rare sounds are transcribed ɓ̥ etc.).
Unusual phonation types
In addition to the most commonly occurring nil phonation (voicelessness) and modal voicing (with the periodic opening and closing of the vocal folds), there are other types of phonation involving more complex glottal configurations:
The vocal folds are vibrating but the glottal closure is incomplete, so that the voicing is somewhat inefficient and air continues to leak between the vocal folds throughout the vibration cycle with audible friction noise. A breathy voiced glottal approximant (ɦ) can be heard as an intervocalic allophone of English /h/, e.g. in behind. A breathy voiced stop (bɦ, dɦ, gɦ etc.) is often followed by an ɦ-like offglide that delays the onset of modal voicing – this is the normal pronunciation of ‘voiced aspirated stops’ such as Hindi bh, dh etc.
Slack (lax) voice
This term is to describe the pronunciation of consonants with a glottal opening slightly wider than that occurring in modal voice. They are often referred to informally as lenis or half-voiced (b̥, d̥, z̥ etc.). In Chinese, many Australian languages and elsewhere the ‘intermediate’ phonation type of slack stops confuses European listeners, so that different transcription systems may use p or b for the same sound.
Creaky voice(also called laryngealisation or ‘vocal fry’, especially in the US)
The arytenoid cartilages in the larynx are ‘adducted’, i.e. drawn together; as a result, the vocal folds are compressed rather tightly . The folds are relatively slack and compact, forming a large, irregularly vibrating mass. The frequency of the vibration is very low (20-50 pulses per second) and the airflow through the glottis is very slow. Creaky voiced (laryngealised) sounds are transcribedd̰, m̰ etc. A slight degree of laryngealisation (stiff voice) is symbolised p*, t*, k* by Ladefoged & Maddieson; they also use ∗ for a ‘creaky voiced glottal approximant’ (diminution of energy between adjacent vowels). Stiff voiced consonants occur e.g. in Korean.