Of the six stops that would be expected from the most common pattern worldwide—that is, three places of articulation plus voicing ()— and are the most frequently missing, being absent in about 10% of languages that otherwise have this pattern. The lack of a
voiceless bilabial stop is an
areal feature. Missing , (when the language uses voicing to contrast stops) on the other hand, is widely scattered around the world, for example /ɡ/ is not a native phoneme of Belarusian, Dutch, Czech, and Slovak and occurs only in borrowed words in those languages. A few languages, such as
Modern Standard Arabic and part of the
Levantine dialects (e.g.
Lebanese and
Syrian), are missing both, although most of the other
Arabic dialects have in their native phonemic systems as a reflex of or less commonly of . It seems that is somewhat more difficult to articulate than the other basic stops.
Ian Maddieson speculates that this may be due to a physical difficulty in voicing velars: Voicing requires that air flow into the mouth cavity, and the relatively small space allowed by the position of velar consonants means that it will fill up with air quickly, making voicing difficult to maintain in for as long as it is in or . This could have two effects: and might become confused, and the distinction is lost, or perhaps a never develops when a language first starts making voicing distinctions. With uvulars, where there is even less space between the
glottis and tongue for airflow, the imbalance is more extreme: voiced is much rarer than voiceless . In many
Indo-Aryan languages, such as
Hindustani, plain and
aspirated are in
contrastive distribution. ==See also==