systems are often studied in abstraction from the geographical region in which
the language is spoken. Yet as is well
known, all languages show some degree of influence from the languages with
which they are in contact. Areal
properties or "Sprachbünde" occur over regions often embracing many
genetically diverse languages, and many aspects of the phonological structure
of a language are best explained in terms of language contact. This point can be illustrated by the distribution
of implosive sounds (sounds produced by drawing in air at their release) in
African languages. These sounds are
mostly concentrated in the Sudanic belt, extending laterally from the
Distribution of implosives in a sample of 150 African languages. Black circles show languages having implosives, white circles show languages lacking them. (Small circles = languages with less than 1m speakers, medium-sized circles = languages with 1-10m speakers, large circles = languages with over 10m speakers.)
The square at left highlights an area in
which implosives are mostly absent.
This area extends from the
N. Clements & Annie Rialland, "