title_body: Can features in the physical environment meaningfully affect the development of a local language's phonology?
upvoted_answer: There has also been evidence that suggests that ejectives tend to occur more frequently in areas of higher elevation, perhaps due to their being easier to produce in these regions:
  
  
    We present evidence that the geographic context in which a language is spoken may directly impact its phonological form. We examined the geographic coordinates and elevations of 567 language locations represented in a worldwide phonetic database. Languages with phonemic ejective consonants were found to occur closer to inhabitable regions of high elevation, when contrasted to languages without this class of sounds. In addition, the mean and median elevations of the locations of languages with ejectives were found to be comparatively high. [...] we offer two plausible motivations for [this correlation's] existence. We suggest that ejective sounds might be facilitated at higher elevations due to the associated decrease in ambient air pressure, which reduces the physiological effort required for the compression of air in the pharyngeal cavity–a unique articulatory component of ejective sounds. In addition, we hypothesize that ejective sounds may help to mitigate rates of water vapor loss through exhaled air. [...] Our results reveal the direct influence of a geographic factor on the basic sound inventories of human languages.
  
  
  (emphasis mine)