My primary research interests include historical linguistics, semantics and meaning changes, the semantics of grammatical constructions, cognitive linguistics, metaphor and iconicity, subjectivity and viewpoint, the relationship between language and gesture, and the Celtic language family. My 1990 book, From Etymology to Pragmatics (Cambridge University Press), explores generalizations about synchronic and diachronic patterns of meaning in the areas of model verbs and conjunctions. My 2005 book, Mental Spaces in Grammar: Conditional Constructions (CUP 2005), was coauthored with Barbara Dancygier, and examines the syntax and semantics of a wide range of English conditional constructions, using a Mental Spaces model of semantics. More recently, Dancygier and I co-edited Viewpoint in Language: A Multi-Modal Perspective (CUP 2012); and our co-authored Cambridge linguistics textbook Figurative Language was published in March 2014. I have published articles on topics including modality, polysemy, metaphor, conditional constructions, grammatical meaning, performativity, gesture, and Medieval Welsh poetics.