The ease with which certain sounds are produced in different climes plays a role in the development of spoken languages. Christopher Intagliata reports
K. Brinker, G. Antos, W. Heinemann, and S. Sager (Eds.) Handbücher zur Sprach- und Kommunikationswissenschaft / Handbooks of Linguistics and Communication Science de Gruyter, Berlin, (2001)
K. Brinker, G. Antos, W. Heinemann, and S. Sager (Eds.) Handbücher zur Sprach- und Kommunikationswissenschaft / Handbooks of Linguistics and Communication Science de Gruyter, Berlin, (2000)
B. Hecht, and D. Gergle. Proceedings of the SIGCHI Conference on Human Factors in Computing Systems (CHI '10), Atlanta, GA, USA, page 291--300. New York, ACM, (2010)
F. Ferri, P. Grifoni, and S. Paolozzi. Knowledge-Based Intelligent Information and Engineering Systems: KES 2007 -- WIRN 2007, 11th International Conference, KES 2007, XVII Italian Workshop on Neural Networks, Vietri sul Mare, Italy, volume 4693 of Lecture Notes in Artificial Intelligence, Springer, Berlin, (2007)