The Logical Problem of Language Change: A Case Study of European Portuguese
In this article we present new results of a novel computational approach to the interaction of two important cognitive-linguistic phenomena: (1) language learning; and (2) language change over time (diachronic linguistics). We exploit the insight that while language learning takes place at the individual level, language change is more properly regarded as an ensemble property that takes place at the level of populations of language learners. We show by analytical and computer simulation methods that language learning can be regarded as the driving force behind a dynamical systems account of language change. We apply this model to the specific case of historical change from Classical Portuguese to European Portuguese, demonstrating how a particular language learning model coupled with data on the differences between Classical and European Portuguese leads to specific predictions for possible language-change envelopes. The main investigative message of this paper is to show how this methodology can be applied to a specific case, that of Portuguese. The main moral underscores the individual/population difference; we show that simply because an individual will choose a particular grammar does not mean that all other grammars will be eliminated. 1. Language Change: An Apparent Paradox