Gregory Guy specializes in sociolinguistics, historical linguistics, phonetics and phonology. In sociolinguistics he has worked extensively on language variation and change, with emphasis on variation and linguistic theory, social aspects of variation and change and the social and linguistic distribution of language change in progress, and quantitative research methodology (the statistical modelling of variability). His current research focuses on the representation of language variation in linguistic theory. Other interests include phonological and syntactic variables in English, Portuguese and Spanish, historical linguistics, Romance linguistics (his areas of language specialization include English, Portuguese and Spanish), phonological theory, pidgin and creole studies, phonetics, and sociolinguistic universals.