Applying insights from variationist linguistics to historical change mechanisms that have affected the consonantal system of English, Daniel Schreier reports findings from a historical corpus-based study on the reduction of particular consonant clusters and compares them with similar processes in synchronic varieties, thus defining consonantal change as a phenomenon involving psycholinguistics, sociolinguistics, phonological theory and contact linguistics. Moreover, he weighs the impact of external and internal effects on causation, examining data from a total of 15 varieties with different time depths and social histories.