Meg graduated from the University of Oxford in 1974 and received her PhD from the University of Edinburgh in 1978. As a member of the Middle English Dialect Project, under the direction of Angus McIntosh, she contributed to the production of A Linguistic Atlas of Late Mediaeval English (LALME) (AUP/Mercat Press, 1986). Since then, at the department's Institute for Historical Dialectology, she has been engaged in a major research project in collaboration with Keith Williamson, and more recently with Roger Lass, to create A Linguistic Atlas of Early Middle English ( LAEME). The LAEME electronic text corpus, with accompanying software and theoretical introduction, is now available as an interactive website. She has written on late Middle English, most notably with Michael Benskin — ‘Translations and Mischsprachen in Middle English Manuscripts', in So meny people longages and tonges, philological essays in Scots and mediaeval English presented to Angus McIntosh , ed. Michael Benskin and M.L. Samuels, pp. 55–106 (1981). She has published extensively on early Middle English, including A Catalogue of Sources for a Linguistic Atlas of Early Medieval English (Cambridge: D.S. Brewer, 1993) and many articles arising out of the investigation of early Middle English texts for LAEME.

The methodology employed for LAEME involves transcribing texts from original manuscripts and ‘tagging' them for analysis and localisation. The close scrutiny involved in this work has led not only to assessment of the diatopic and diachronic variation in early Middle English phonology, morphology, lexis and syntax, but also to a number of studies on textual and linguistic relationships of different versions of texts, early Middle English orthographical systems and new manuscript readings (see publications below).

Since September 2007 Meg has been working, in collaboration with Keith Williamson and Michael Benskin (University of Oslo), towards the creation of an electronic, web-based version of LALME (e-LALME). The project is funded by AHRC and the Mellon Foundation.

Meg contributes to the teaching of Middle English Honours and gives the Middle English lectures of the History of English component in English Language 1. She offers (with Keith Williamson) the ‘Principles and Applicatons of Medieval Dialectology’ option in the department's MSc in English Language and at Honours, and teaches the Middle English palaeography component of the interdepartmental MSc in Medieval Studies. She co-supervised Ela Majocha’s PhD An Onomastic Study of Early Middle English (2005) and is jointly supervising Lauren Stewart’s PhD on Representation of Dialect in 17th-century English drama and Claire McShane's PhD on the use of register in Margery Kempe.