| Summary: | How did language come to have its characteristic structure? Many argue that by understanding those parts of our biological machinery relevant to language, we can explain why language is the way it is. If the hallmarks of language are simply properties of our biological machinery, elicited through the process of language acquisition, then such an explanatory route is adequate. As soon as we admit the possibility that knowledge of language is learned, in the sense that language acquisition is a process involving inductive generalisations, then an explanatory inadequacy arises. Any thorough explanation of the characteristic structure of language must now explain why the input to the language acquisition process has certain properties and not others. This thesis builds on recent work that proposes that the linguistic stimulus has certain structural properties that arise as a result of linguistic evolution. Here, languages themselves adapt to fit the task of learning: they reflect an accumulated structural residue laid down by previous generations of language users. Using computational models of linguistic evolution I explore the relationship between language induction and generalisation based on a simplicity principle, and the linguistic evolution of compositional structures. The two main contributions of this thesis are as follows. Firstly, using a model of induction based on the minimum description length principle, I address the question of linguistic evolution resulting from a bias towards compression. Secondly, I carry out a thorough examination of the parameter space affecting the cultural transmission of language, and note that the conditions for linguistic evolution towards compositional structure correspond to (1) specific levels of semantic complexity, and (2), induction based on sparse language exposure. Ultimately, the story of the evolution of language in humans must depend on an account of the genetic evolution of the biological machinery underlying language. Rather than explicitly encoding the observed constraints on language, I argue that any explanation based on biological evolution should instead aim to explain how the conditions for linguistic evolution, outlined above, came about.
|
|---|
