Demiraj was born on 1 January 1920 in Vlorë. Despite financial difficulties and the lack of academic institutions in Albania, he managed to study and learn Latin, ancient Greek, and the major European languages. After finishing the Madrasa in Tirana in 1939, he studied Albanian language in the two-year curriculum Pedagogical Institute, branch of Albanian language and literature, and later in the High Pedagogical Institute. During 1948–1954 he worked as language and literature teacher in various high schools in Gjirokastër and Tirana. In 1954, he started working as a lector in the same High Pedagogical Institute from where he graduated, and later in the University of Tirana, holding that position until 1990. During 1962–1989, he was in charge of the Albanian language chair, and in the period 1962–1966 he served as deputy dean of the Faculty of History and Philology of the UT. His areas of expertise were: the morphology of modern Albanian, Albanian historical grammar, the history of the Albanian writing, and a special course on Balkan linguistics. In 1989 he became member of the Albanian Academy of Sciences, and was its chairman during 1993-97. Beside his research publications, Demiraj also published many scientific articles inside Albania and abroad on topics as history of the Albanian language, grammar and phonetics, and Balkanology. He has transcribed and adapted the work of Gavril DaraKënga e sprasme e Balës in 1994. He also worked as a translator, having produced the Albanian edition of Martin Eden, a novel by Jack London, in 1959. Demiraj was part of the committee that organized the Orthography Congress of 1972, Kongresi i Drejtshkrimit, where the orthographic rules of the Albanian language were standardized, and he was also a signatory to the orthography. He is the father of linguist Bardhyl Demiraj.
Work
Some of his main works include:
Çështje të sistemit emëror të gjuhës shqipe . Pristina: Pristina University Press, 1972.
Gramatikë historike e gjuhës shqipe. Tirana: Tirana University Press, 1986.
Gjuha shqipe dhe historia e saj . Tirana: Tirana University Press, 1988
*Italian translation: La lingua albanese – origine, storia, strutture. Rende: Centro Editoriale e Librario, Università degli Studi della Calabria, 1997.
Gjuhësi ballkanike . Skopje: Logos-A 1994, republished in Tirana in 2004
Fonologjia historike e gjuhës shqipe, 1996
Prejardhja e Shqiptarëve në dritën e dëshmive të gjuhës shqipe, 1999, a second edition in English as The Origin of the Albanians, 2006
Eqrem Çabej, 1990
Epiri, Pellazgët, Etruskët dhe Shqiptarët, 2008.
Gramatikë e gjuhës shqipe, vëll. I Morfologjia, 1976, other editions 1995, 2002, as editor and co-author.
