Nils-Lennart Johannesson was Professor of English Linguistics at Stockholm University, teaching courses on English syntax, the history of the English language, and Old and Middle English. He has been a member of the board of directors of Arda-sällskapet (the Arda Society), and published several articles about J.R.R. Tolkien's works.
 Bibliography, selected
- 1997: News from the Shire and Beyond - Studies on Tolkien
- "The Speech of the Individual and of the Community in The Lord of the Rings"
- 1994: Nonstandard Varieties of Language. Papers from the Stockholm Symposium, 9–11 April, 1991. Edited by Gunnel Melchers and Nils-Lennart Johannesson. Stockholm Studies in English 84. Stockholm: Almqvist and Wiksell International.
- "Subcreating a Stratified Community: On J.R.R. Tolkien's Use of Non-standard Forms in The Lord of the Rings".
- 1992: Arda 1987, Vol. VII
- "Studies in Tolkien's Language"
- 1988: Arda 1984/1985, Vols. IV & V
- "Sure as Shiretalk - On Linguistic Variation in Hobbit Speech (Part One)"