Between 1993 and 1995 he was Secretary of the International Phonetic Association, and from 1999 to 2003 its Vice-President. He specialises in phonetics and phonology as well as in forensic linguistics. He is currently President of the British Association of Academic Phoneticians. He was one of the co-editors of the 1999 Handbook of the International Phonetic Association, the other being John Esling. He co-designed the language of Parseltongue featured in the Harry Potter films.