Applying insights from variationist linguistics to historical change mechanisms in the English consonant system, Daniel Schreier reports findings from an historical corpus-based study on the reduction of various consonant clusters and compares them with similar processes in synchronic varieties. He therefore defines consonantal change as a strictly interdisciplinary phenomenon that involves fields as distinct as psycholinguistics, sociolinguistics, phonological theory and contact linguistics. Moreover, he pinpoints the impact of external effects through the examination of data from fifteen varieties with different time depths and social contact histories, ranging from language shift, bilingualism and koineisation to pidginisation and creolisation Findings from all these varieties are analysed with the aim of investigating how contact histories foster variation and change; how consonantal change is governed by internal constraints; and also how universal coarticulation patterns are intensified through linguistic contact and transfer of CV/CVC syllable structures.