Recent patterns of global migration have increased the ethnolinguistic diversity of many cities. Urban migration brings about situations in which different processes of language contact can take place, leading to different sociolinguistic outcomes. Heritage languages influence the majority language of first-generation migrants, exhibiting features characteristic of language transfer and second-language learning. Ethnically marked ways of speaking (‘ethnolects’) are normally attributed to the persistence of second-language features in subsequent generations. In this presentation, I discuss a large-scale project designed to investigate the sociolinguistic consequences of ethnolinguistic diversity in Toronto, Canada’s largest city. Recruiting a representative sample of participants of British/Irish background and from the city’s most demographically robust communities (Chinese, Filipino, Greek, Italian, Portuguese, Punjabi), we have obtained samples of English through sociolinguistic interviews conducted and recorded by in-group community members. We compare the overall rates and sociolinguistic conditioning of an array of linguistic variables across different dimensions.