Natural selection has favored the development of a human language so rich in information, that, additionally to meaning, we can also identify the speaker`s sex, emotional state, age, health and social status. Selection has also favored accents and local languages, because they allow the identification of group members (and the exclusion of nonmembers from the group’s resources). The brain uses rules to extract that information, and these rules can fail when applied to alien accents and languages, interpreting, for example, anger or infantilism where there are none.
Boeckx, C., & Piattelli-Palmarini, M. (2005). Language as a natural object–linguistics as a natural science. The linguistic review, 22(2-4), 447-466.
Cohen, E., Atkinson, Q. D., Dediu, D., Dingemanse, M., D. Kinzler, K., Ladd, D. R., ... Cohen, E. (2012). The evolution of tag-based cooperation in humans: The case for accent. Current Anthropology, 53(5), 588-616.
García, M. (2016). Sobre la duración vocálica y la entonación en el español amazónico peruano. Lengua y Sociedad, 14(2), 5-29.
Ikeno, A., & Hansen, J. H. (2007). The effect of listener accent background on accent perception and comprehension. EURASIP Journal on Audio, Speech, and Music Processing, 2007(3), 4.
Lippi-Green, R. (1997). English with an Accent: Language, Ideology, and Discrimination in the United States. New York: Routledge.
McIntosh, I., Sim, D., & Robertson, D. (2004). ‘We Hate the English, Except for You, Cos You’re Our Pal’ Identification of the ‘English’ in Scotland. Sociology, 38(1), 43-59.