- Tutorial Fellow and CUF Lecturer, Hertford College (working half-time from 1998-2004) (from 1990 to 2004)
- Quondam Fellow, All Souls College (from 1990)
- Thesis Fellow, All Souls College (from 1987 to 1990)
- Lecturer, University of Leeds (from 1985 to 1987)
- Lecturer and Fellow, Lady Margaret Hall, Oxford (from 1982 to 1985)
- Postgraduate, Wolfson College, Oxford (from 1980 to 1982)
- Postgraduate, Centre for Medieval Studies, University of Toronto, Canada (from 1979 to 1980)
- Undergraduate, St Anne’s College, Oxford (from 1975 to 1978)
- Currently working on the history and revision of the Oxford English Dictionary since the completion of the first edition in 1928
- Textual criticism, especially in the Middle English period
- Old and Middle English and History of the Language for the College, and give lectures and seminars on these subjects for the University
- Research website (OED)
- Leverhulme Research Fellow (2009).