What factors shaped the development of linguistic diversity? Apparently the climate of a region also played a role in the development of the characteristics of the language of its residents, according to a study. Accordingly, languages that emerged in warmer regions tend to be slightly louder than those from cooler parts of the world. This likely has to do with physical properties of air that influence how easily speech can be produced and heard, the scientists explain.
Being able to convey complex information to our fellow human beings using specific sound sequences is a key element of the success of our species. The focus is often on the question of how the concept of language fundamentally emerged in the course of evolution. But interestingly, the communication system was also later subject to a kind of evolutionary process: many, sometimes very different, languages developed among people in different regions of the world. Complex cultural factors and mutual influences played important roles. A team of Chinese and German researchers has now investigated the question of whether traces of the influence of a physical factor can also be found in the world's languages.
Has the climate also shaped languages?
Specifically, they were concerned with the possible influence of the average air temperature, which in turn is linked to humidity. In principle, it seems clear that the different properties of the air can affect the production of speech and the propagation of sound waves and thus the ability to perceive: “On the one hand, the dryness of the cold air represents a challenge for the production of voiced sounds, which are a vibration of the require vocal cords. On the other hand, warm air tends to limit voiceless sounds by absorbing their high-frequency energy,” explains co-author Søren Wichmann from the Christian Albrechts University in Kiel. This connection gave rise to the assumption that warmer climates could have favored the development of louder speech elements. Accordingly, the languages there must have increased sonority, as the technical term goes.
The researchers examined the extent to which such a pattern is actually reflected in the world's languages by analyzing the information from an extensive language database: It currently contains the basic vocabulary of 5,293 languages and is constantly being expanded. The team used automatic analysis tools to track the frequency and extent of sonorous elements in the languages. They were then able to place the results in the context of the climate in which the respective languages developed.
Where it's warm, it sounds more sonorous
As they report, a significant connection actually emerged: “Overall, we found a clear relationship between the mean sonority of language families and the mean annual temperature. In simple terms, this means: Languages in warmer regions of the world are louder than those in colder regions,” summarizes Wichmann. Specifically, it could be that the formulation of the sonorous sounds was comparatively difficult in the cold regions, but was less necessary due to the better transmission values in the air. In warm regions the reverse was true. In a kind of evolutionary process, this then led to corresponding adaptations of the languages.
According to the study, languages that occur around the equator in particular have a high average sonority. Languages in Oceania and Africa have the highest corresponding index. The team found the strongest contrast to this in the Salish languages on the northwest coast of North America: the scientists report that this is the world record for the lowest sonority among human languages.
Possible references to migration stories
However, as they point out, this is a pattern that only emerges on a large scale. There are some exceptions that do not fit the pattern: For example, in Central America and mainland Southeast Asia there are languages that have a rather low mean sonority, even though they are spoken in very warm regions. One reason could have been the migration history of population groups and their languages: The exceptions suggest that the effects of temperature on sonority develop only slowly and only shape the sounds of a language over long periods of time.
This could also be a further aspect of the study results, Wichmann concludes: “It could reveal information about the history of societies: When languages adapt to the environment in a slow process that lasts thousands of years, then they provide some clues the environment of their predecessor languages,” says the linguist.
Source: Christian Albrechts University of Kiel, specialist article: PNAS Nexus, doi: 10.1093/pnasnexus/pgad384