When Mikael Reuter worked at the University of Helsinki (and also for a short while after) his main area of research was Swedish phonetics, particularly the pronunciation of Swedish in Helsinki. Above all, he researched the quality of vowels and the relative duration of sounds and syllables. The research gave rise, among other things, to an unpublished licentiate thesis, Kvantitet i Helsingforssvenskan (1982). Elsewhere, as a research and teaching assistant and visiting lecturer, he primarily taught Swedish phonology. After receiving a post at the Institute for the Languages of Finland, Reuter conducted no further academic research, with the exception of the completion of his licentiate degree. Instead, he has conducted applied research on the special characteristics of Fenno-Swedish as compared to Swedish in Sweden.

As the leading language planning expert at the department of Swedish at the Institute for the Languages of Finland, Reuter worked to maintain the Swedish language and improve its position in Finland. His goal has been to ensure that Swedish can also be used in all sectors of society in the future. Language planning and maintenance is much more than the correct use of language and the avoidance of ‘Finlandisms’. Those issues are naturally important, particularly for minority language groups like the Swedish-speaking Finns. For Reuter what has also been important is cooperation with journalists, editors and translators, the publishing of dictionaries, manuals, and the periodical Språkbruk, writing language columns, various courses and seminars and Nordic language cooperation.