Editing Sonority hierarchy (section)

==Ecological patterns in sonority==

The sonority ranking of speech sounds plays an important role in developing phonological patterns in language, which allows for the [[Intelligibility (communication)|intelligible]] transmission of speech between individuals in a society. Differences in the occurrence of particular sounds in languages around the world have been observed by numerous researchers. It has been suggested that these differences are as a result of [[Ecological selection|ecological pressures]].

This understanding was developed from the acoustic adaptation hypothesis, which was a theory initially used to understand differences in bird songs across varying habitats.<ref name="BoncoraglioSaino2007">{{cite journal|last1=Boncoraglio|first1=Giuseppe|last2=Saino|first2=Nicola|title=Habitat structure and the evolution of bird song: a meta-analysis of the evidence for the acoustic adaptation hypothesis|journal=Functional Ecology|volume=21|issue=1|year=2007|pages=134–142 |issn=0269-8463|doi=10.1111/j.1365-2435.2006.01207.x|doi-access=free|bibcode=2007FuEco..21..134B }}</ref> However, the theory has been applied by researchers as a base for understanding why differences are shown in speech sounds within spoken languages around the world.<ref name="Maddieson2018">{{cite journal|last1=Maddieson|first1=Ian|title=Language Adapts to Environment: Sonority and Temperature|journal=Frontiers in Communication|volume=3|year=2018|issn=2297-900X|doi=10.3389/fcomm.2018.00028|doi-access=free}}</ref>

===Climates===
Maddieson and Coupé’s<ref name="Maddieson2018" /> study on 633 languages worldwide observed that some of the variation in the sonority of speech sounds in languages can be accounted for by differences in climate. The pattern follows that in warmer climatic zones, language is more sonorous compared to languages in cooler climatic zones which favour the use of consonants. To explain these differences they emphasise the influence of atmospheric absorption and turbulence within warmer, ambient air, which may disrupt the integrity of acoustic signals. Therefore, employing more sonorous sounds in a language may reduce the distortion of soundwaves in warmer climates. 
Fought and Munroe<ref name="FoughtMunroe2016">{{cite journal|last1=Fought|first1=John G.|last2=Munroe|first2=Robert L.|last3=Fought|first3=Carmen R.|last4=Good|first4=Erin M.|title=Sonority and Climate in a World Sample of Languages: Findings and Prospects|journal=Cross-Cultural Research|volume=38|issue=1|year=2016|pages=27–51|issn=1069-3971|doi=10.1177/1069397103259439|s2cid=144410953}}</ref> instead argue that these disparities in speech sounds are as a result of differences in the daily activities of individuals in different climates. Proposing that throughout history individuals residing in warmer climates tend to spend more time outdoors (likely engaging in agricultural work or social activities), therefore speech requires effective propagation of sound through the air for acoustic signals to meet the recipient over these long distances, unlike in cooler climates where people are communicating over shorter distances (spend more time indoors).
Another explanation is that languages have adapted to maintain [[homeostasis]].<ref name="Vliert2008">{{cite book|author=Evert Van de Vliert|title=Climate, Affluence, and Culture|url=https://books.google.com/books?id=zGSH2WBnqA0C&pg=PR5|date=22 December 2008|publisher=Cambridge University Press|isbn=978-1-139-47579-2|pages=5–}}</ref> [[Thermoregulation]] aims to ensure body temperature remains within a certain range of values, allowing for the proper functioning of cells. Therefore, it has been argued that differences in the regularity of phones in a language are an adaptation which helps to regulate internal bodily temperatures. Employing the use of open vowels like /a/ which is highly sonorous, requires the opening of [[Vocal tract|vocal articulators]]. This allows for air to flow out of the mouth and with it evaporating water which reduces internal bodily temperatures. In contrast, voiceless plosives like /t/ are more common in cooler climates. Producing this speech sound obstructs airflow out of the mouth due to the constriction of vocal articulators. Thus, reducing the transfer of heat out of the body, which is important for individuals residing in cooler climates.

===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.

===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.