A study of more than 550 languages worldwide found those spoken in high-altitude regions contain more "ejective consonant" sounds made with a burst of air than languages closer to sea level, LiveScience.com reported Wednesday.
Study author Caleb Everett said ejectives may be more common at higher altitudes because they're easier to produce or possibly because they reduce water loss from the mouth in the drier environment.
Everett said he investigated how other aspects of geography, specifically altitude, could be linked to certain sounds, or phonemes, in a language. He looks at ejectives, a class of sounds produced by puffs of air in the mouth rather than the lungs.
Everett said he suspected these sounds might be more common at high altitudes where lower air pressure would make them easier to produce.
Everett analyzed phoneme data on 567 languages from the World Atlas of Linguistic Structures Online, comparing data to the altitudes where the languages were spoken, LiveScience.com said.
Languages containing ejective sounds were found at or near five of the six major inhabited high-altitude regions, including the Americas, southern Africa and Eurasia, Everett said.
The exception was the Himalayan Plateau, which isn't home to any languages containing ejectives.
"It is not particularly surprising that one region should present such an exception," Everett said, "and in fact it strikes us as remarkable that only one region presents an exception."
The findings were detailed Thursday in Plos One.