Paul Warren's main research interests are in psycholinguistics, experimental phonetics, including intonation, sociophonetics, and New Zealand English phonetics and phonology. His book Uptalk: the phenomenon of rising intonation (2016, Cambridge University Press), explores the use of high rising terminal intonation across varieties of English and in other languages.

Paul has also been involved in extensive research in spoken word recognition, with a particular focus on the interpretation of acoustic-phonetic cues and of naturally-occurring variation resulting from coarticulation and discourse-level factors such as informational status. He also has a long-standing interest in the relationship of intonation and sentence comprehension, an area which is the subject of his doctoral dissertation as well as of many recent articles and his edited volume Prosody and Parsing (1996, Erlbaum)

Paul is a member of various professional organisations including the Linguistic Society of New Zealand, the International Phonetic Association, the Association for Laboratory Phonology (founding member) and the Australasian Speech Science and Technology Association. He is currently on the editorial boards of the Journal of the International Phonetic Association, Laboratory Phonology and te Reo, and regularly reviews submissions for a number of other journals