Implosive consonant

Implosive consonants are stops (rarely affricates) with a mixed glottalic ingressive and pulmonic egressive airstream mechanism.^[1] That is, the airstream is controlled by moving the glottis downward in addition to expelling air from the lungs. Therefore, unlike the purely glottalic ejective consonants, implosives can be modified by phonation, which is almost universally voice. Contrastive implosives are found in approximately 13%^[2] of the world's languages.

In the International Phonetic Alphabet, implosives are indicated by modifying a voiced stop letter with a hook top: ⟨ɓ ɗ ʄ ɠ ʛ ⟩.

Articulation

During the occlusion of the stop, pulling the glottis downward rarefies the air in the vocal tract. The stop is then released. In languages where implosives are particularly salient, this may result in air rushing into the mouth, before flowing out again with the next vowel. (Thus the name "implosive".) However, probably more typically there is no movement of air at all, contrasting with the burst of the pulmonary plosives. This is the case with many of the Kru languages, for example. Note that this means implosives are phonetically sonorants (i.e. not obstruents) as the concept of sonorant is usually defined. However, phonologically implosives can pattern as both, that is they may be phonological sonorants or obstruents depending on the language. Clements (2002) actually proposes that implosives are phonologically neither obstruents nor sonorants, and that they need to be described by the features -obstruent and -sonorant.

The vast majority of implosive consonants are voiced, meaning that the glottis is only partially closed. Because the airflow required for voicing reduces the vacuum being created in the mouth, implosives are easiest to make with a large oral cavity. Thus bilabial [ɓ] is the easiest implosive to pronounce, and also most common around the world. Velar [ɠ], on the other hand, is quite rare (and uvular [ʛ] even rarer). This is the opposite pattern to the ejective consonants, where it is the velar articulation that is most common, and the bilabial that is rare.

Types of implosives

The attested voiced implosive stops are:

• voiced bilabial implosive [ɓ]
• voiced dental implosive [ɗ̪ ]
• voiced alveolar implosive [ɗ ]
• voiced retroflex implosive [ᶑ ] (not an IPA symbol)
• voiced palatal implosive [ ʄ ]
• voiced velar implosive [ɠ ]
• voiced uvular implosive [ʛ ]

Implosive affricates and fricatives are extremely unusual. There are no IPA symbols for implosive fricatives. Conceptually the implosive hook could be added to the letters for voiced fricatives, though the labiodental would be confused with the labiodental flap [ⱱ].

Voiceless implosives

Consonants variously called "voiceless implosives", "implosives with glottal closure",^[3] or "reverse ejectives" involve a slightly different airstream mechanism, purely glottalic ingressive.^[1] Here the glottis is closed, so no pulmonic airstream is possible. The IPA once dedicated symbols ⟨ƥ ƭ ƈ ƙ ʠ ⟩ to these sounds, but these were withdrawn in 1993. They are now transcribed ⟨ɓ̥ ɗ̥ ʄ̊ ɠ̊ ʛ̥ ⟩ or occasionally ⟨pʼ↓ tʼ↓ cʼ↓ kʼ↓⟩. Some authors use a superscript left pointer, ⟨p˂ t˂ c˂ k˂⟩, but this is not an IPA symbol and has other uses.

The attested voiceless implosive stops are:

• voiceless bilabial implosive [ɓ̥]
• voiceless alveolar implosive [ɗ̥ ]
• voiceless palatal implosive [ ʄ̥ ]

Paraphonemic in English is:

• voiceless velar implosive [ɠ̊ ]

Also claimed in the literature:

• voiceless uvular implosive [ʛ̥ ]

Lendu has been claimed to have /ɓ̥ ɗ̥ ɠ̊/. However, these may actually be creaky-voiced implosives.^[3]

Occurrence in languages

Implosives are commonplace among the Sub-Saharan African languages, are widespread in Southeast Asia (e.g. Vietnamese), and are found in a few languages of the Amazon Basin. They are rarely reported elsewhere, but do occur in scattered languages such as the Mayan languages in North America, and Sindhi in the Indian subcontinent. They appear to be entirely absent from Europe and Australia, even from the exotic ceremonial language Damin, which uses every other possible airstream mechanism. However, fully voiced stops are often slightly implosive, although this is not always described explicitly when there is no contrast with modal-voiced plosives. This is found around the world, from Maidu to Thai to many Bantu languages, including Swahili.

Sindhi has an unusually large number of contrastive implosives, with /ɓ ᶑ ʄ ɠ/.^[3][4] Although Sindhi has a dental-retroflex distinction in its plosives, with /b d ɖ ɟ ɡ/, this contrast is neutralized in the implosives. A contrastive retroflex implosive /ᶑ / may however occur in Ngad'a, a language spoken in Flores, Indonesia.^[5]

For more examples please refer to the articles on the individual implosives.

Voiceless implosives are quite rare but are found in languages as varied as the Owere dialect of Igbo in Nigeria (/ƥ/ /ƭ/), Krongo in Sudan, the Uzere dialect of Isoko, the closely related Lendu and Ngiti languages in the Democratic Republic of Congo, Serer in Senegal (/ƥ ƭ ƈ/), and some dialects of the Poqomchi’ and Quiche languages in Guatemala (/ƥ ƭ/). Owere Igbo has a seven-way contrast among bilabial stops, /pʰ p ƥ bʱ b ɓ m/, and its alveolar stops are similar. It does not appear that the dorsal stops [ƙ] [ʠ] are attested in the literature as speech sounds,^[6] though /ʠ/ has been claimed for Kaqchikel. Some English speakers use a voiceless velar implosive [ƙ] to imitate the "glug-glug" sound of liquid being poured from a bottle, though others use a voiced implosive [ɠ].^[7]

The rare imploded affricates occur in Kung-Ekoka and Hendo (a Bantu language). Several Central Sudanic languages, such as Mangbetu, have implosive labiodental fricatives [vʼ↓], which are "strongly imploded, the lower lip briefly pulled back into the mouth".

References

Bibliography

• Clements, George N.; Sylvester Osu (2002). "Explosives, Implosives, and Nonexplosives: the Linguistic Function of Air Pressure Differences in Stops". Laboratory Phonology. 7. Berlin: Mouton de Gruyter. pp. 299–350. http://nickclements.free.fr/publications/2002a.pdf. Retrieved 2010-01-08. 
• Demolin, Didier; Ngonga-Ke-Mbembe, Hubert; & Soquet, Alain. (2002). Phonetic characteristics of an unexploded palatal implosive in Hendo. Journal of the International Phonetic Association, 32, 1-15.
• Ladefoged, Peter; Maddieson, Ian (1996). The Sounds of the World's Languages. Oxford: Blackwell. ISBN 0-631-19814-8. 
• Maddieson, Ian. (1984). Patterns of sounds. Cambridge studies in speech science and communication. Cambridge: Cambridge University Press.