Atkinson, M. , Kirby, S. & Smith, K.
University of Edinburgh
A learner's linguistic input is more variable if it comes from a greater number of speakers. Higher variability has been proposed to systematically influence individual-level acquisition of morphology, which could in turn determine group-level characteristics of a language. As a learner's social network is likely to be larger in larger social groups, it is thought that they may receive more variable input in larger groups. Increased input variability may therefore explain why languages spoken by larger communities have less complex morphology than those spoken in smaller groups. In hindering the acquisition, and hence cross-generational transfer, of complex morphology, higher variability may cause structural simplification.
We assess this claim in two experiments which investigate the effect of input variability on language learning, considering its influence on a learner's ability to segment a continuous speech stream, and in the acquisition of a morphologically complex miniature language. We find that increased variability appears to have no effect in either case. Language learners are able to use distributional cues to segment input data, and acquire complex morphology, even when their input is more variable. Input variability does not explain why languages with a larger number of speakers are simpler.