Editing Sonority hierarchy (section)

===Vegetation===
A positive correlation exists, so that as temperature increases, so does the use of more sonorous speech sounds. However, the presence of dense vegetation coverage leads to the correlation occurring oppositely,<ref name="EmberEmber2007">{{cite journal|last1=Ember|first1=Carol R.|last2=Ember|first2=Melvin|title=Climate, Econiche, and Sexuality: Influences on Sonority in Language|journal=American Anthropologist|volume=109|issue=1|year=2007|pages=180–185|issn=0002-7294|doi=10.1525/aa.2007.109.1.180}}</ref> so that less sonorous speech sounds are favoured by warmer climates when the area is covered by dense vegetation. This is said to be because in warmer climates with dense vegetation coverage individuals instead communicate over shorter distances, therefore favour speech sounds which are ranked lower in the sonority hierarchy.