Extensive research on human physiology suggests that really dry air makes it hard for us to use our vocal cords, very precisely. ? an anthropological linguistic professor at the university of Miami. He and his colleagues recently investigated that dry throat phenomenon in regards to complex tonal languages like cantonese, where various combinations of rising and falling tones can actually change the meaning of a word, as opposed to non- tonal languages like English or Italian. In the non-toner, the fundamental meaning is the same whether I say word, word or word. By mapping the distribution of more than thirty-seven tonal and non-tonal languages, Everge and his colleagues found that tonal languages tend to cluster in warm and humid areas, and they are ten times less prevelent in dry sub-freezing climate like Syberia compared with non-tonal languages. The study is in the proceedings of the National Academy of Sciences. Of course it's physically possible they speak tonal languages in a cold place.

  Obviously the speakers of contanese, for instance, can communicate in Siberia and in other dry places.

  The big picture, Everest says, is that languages evolve in relation to where it's spoken.

  Language does not evolve in vacuum. It is not impervious to the effects of the environment. This is ecologies impact human behavior and adaptive processes of human cultures in myriad ways. They seem to also influence the ways which the language develops