Keys to the history of English : diachronic linguistic change morpho syntax and lexicography : selected papers from the 21st ICEHL This volume brings together contributions selected from papers delivered at the 21st International Conference on English Historical Linguistics (ICEHL Leiden 2021). The contributions deal with various aspects of English language across time and geographical space shedding light on both long term developments and singular documents of particular linguistic interest. A wide range of methodologies are represented including corpus linguistics acoustic phonology and philology. Chapters showcase work on syntax and word order (parataxis and hypotaxis from Old to Late Modern English; left dislocation in Old English; do support in Scots) diachronic linguistic change (phonological developments of lateral l in English; modality in noun clauses from Old to Early Modern English; editorial practices of Middle English punctuation across time) and lexicography and lexis (Old English glosses of the Durham Ritual; Old English lexicographers from 17th century Germany; lexical differences between Old and Middle English; Yiddish loanwords in English). This volume will be of interest to those working on morphology syntax and lexicography of English historical linguistics language change history of linguistics computational historical linguistics and related sub disciplines