Individual variation and the coarticulatory path to sound change: agent-based modeling of /str/ in English and Italian

Abstract

This study is concerned with sound change in single populations. Sources differ as to whether such sound changes are attributed to the accumulation of coarticulatory variation, i.e. shared tendencies, or whether idiosyncratic variation is necessary to shift population norms. Using agent-based modeling, this study compares effects of interaction amongst members of single populations with (English-speaking) and without (Italian-speaking) coarticulatory variation involving /s/-retraction in /str/. After interaction, directional shifts /s/ -> /ʃ/ are found in English but not Italian /str/. Manipulating starting conditions to remove outlier individuals from the group of interacting agents has little effect on population-level outcomes. These results provide empirical support for the idea that sound change originates in phonetic variation that is common, rather than exceptional, in a population.