Editing Sonority hierarchy (section)

===Altitude===
Everett, (2013)<ref name="AronoffEverett2013">{{cite journal|last1=Aronoff|first1=Mark|last2=Everett|first2=Caleb|title=Evidence for Direct Geographic Influences on Linguistic Sounds: The Case of Ejectives|journal=PLOS ONE|volume=8|issue=6|year=2013|pages=e65275|issn=1932-6203|doi=10.1371/journal.pone.0065275|pmid=23776463|pmc=3680446|bibcode=2013PLoSO...865275E|doi-access=free}}</ref> suggested that in high elevation regions such as in the [[Andes]], languages regularly employ the use of ejective plosives like /[[velar ejective|kʼ]]/. Everett argued that in high altitude areas, with reduced ambient air pressure, the use of ejectives allows for ease of articulation when producing speech. Moreover, as no air is flowing out of the vocal folds, water is conserved whilst communicating, thus reducing dehydration in individuals residing in high elevation regions.

A range of other additional factors have also been observed which affect the degree of sonority of a particular language such as precipitation and sexual restrictiveness.<ref name="EmberEmber2007" /> Inevitably, the patterns become more complex when considering a range of ecological factors simultaneously. Moreover, large amounts of variation are shown which may be due to patterns of migration.