Professor Ó Maolalaigh has expertise in the Gaelic languages across all historical periods down to the present day. His published works engage with the major areas of Gaelic linguistics. He has a particular interest in the historical development of the Gaelic languages and their emergence in modern forms. His research includes linguistic variation, Gaelic dialectology, corpus linguistics, lexicology, onomastics and Gaelic manuscript collections of the modern period. He has developed a range of externally funded pioneering initiatives, which include digital humanities resources to transform advanced research and learning in Celtic and Gaelic Studies, many of which are of direct relevance to language policy in Scotland.