Integrating Approaches to the Role of Metaphor in the Evolutionary Dynamics of Language

Metaphor occupies a central role not only in language use, but also in language change and evolution. Specifically, semantic extension motivated by metaphor plays an important role in extending the lexicon of languages. It is this process that enables the emergence of one of the key properties of modern languages, namely that they are open-ended, systematic, polysemous, structured semiotic systems. Here, we review results from three approaches whose integration presents an important cornerstone for an interdisciplinary account of the role of metaphor in the evolutionary dynamics of language: (1) Historical linguistics and diachronic semantics (2) Computational approaches and natural language processing, and (3) Experimental semiotics. Research in historical linguistics has shown that metaphor is a major mechanism of semantic change. Diachronic semantic analyses have not only mapped detailed historical trajectories of semantic extension motivated by metaphor, but also identified common metaphoric pathways of change as well as shared cognitive principles underlying them. Computational approaches and natural language processing have used findings and data from historical linguistics in attempts to automate the detection of metaphoric semantic change and to build data-driven models of the principles underlying it. Experimental semiotics is a paradigm in which participants have to create novel communication systems in the absence of language. It represents a paradigm that can investigate cultural linguistic evolution and the emergence of metaphors and metaphorical extensions under controlled laboratory settings to shed light on the interactional and cognitive principles involved in it. Combining results from these approaches represents an important first step towards an interdisciplinary, integrative account of the role of metaphor, and processes of polysemous meaning extension more generally, in the evolutionary dynamics of language.