Constant Rate Effects and Beyond: Modelling Interactions of Language-Internal and Language-External Factors in Language Change

语言的变化受到多种因素的制约，包括语法、语言学习的心理事实、言语产生和感知的特性以及语言交际的社会嵌入。尽管语言学研究已经分别提供了关于这些因素的丰富信息，但对它们之间的相互作用所知相对较少。其原因主要是方法论上的：研究许多因素的复杂相互作用需要采用一种新的方法，在这种方法中，语言和语言社区被视为复杂的动态系统，随着时间的推移，随着一些参数的变化而演变。我的研究目的是阐明语言变化中内部和外部因素的相互作用。尽管语言学习心理和各种语音处理效应等内部因素可能会影响语言变化的方向，但严格来说，语言外部因素起着至关重要的作用：例如，这些因素包括对不同语言变体的社会评价，以及语音社区组织核心社会网络的形成和演变。我通过数学和计算机模拟对语言使用和语言学习进行建模，并将这些模型的预测与经验数据进行比较，来解决这些相互作用的问题。不同模型做出的不同预测揭示了语言变异和语言变化背后的生物、心理和社会过程；通过这种方式，复杂系统建模有助于对语言如何以及为什么变化的持续争论。

Language change is conditioned by a variety of factors, including grammar, the psychological facts of language learning, properties of speech production and perception, and the social embedding of linguistic communication. Although research in linguistics has produced a wealth of information about each of these factors separately, relatively little is known about their interactions. The reason for this is mainly methodological: studying the complex interactions of a number of factors requires adoption of a new kind of approach, in which languages and language communities are viewed as complex dynamical systems evolving through time in response to variation in a number of parameters.The aim of my research is to elucidate the interactions of internal and external factors in language change. Even though internal factors such as the psychology of language learning and various speech processing effects may shape the direction of language change, a crucial role is played by factors which are strictly speaking external to language: these include the social evaluation of different linguistic variants and the shape and evolution of the social network at the heart of the organization of a speech community, for example. I tackle the problem of these interactions by modelling language use and language learning mathematically and with computer simulations, and by comparing the predictions of these models against empirical data. The different predictions made by different models shed light on the biological, psychological and social processes underlying linguistic variation and language change; in this way, complex-systems modelling contributes to the ongoing debate on how and why languages change.