Slavic microlanguages are literary and linguistic forms that exist alongside the better-known Slavic languages of historically prominent nations. Aleksandr Dulichenko coined the term "(literary) microlanguages" at the end of the 1970s; it subsequently became a standard term in Slavistics.
Slavic microlanguages exist both as geographically and socially peripheral dialects of more well-established Slavic languages and as completely isolated speech forms. They often enjoy a written form, a certain degree of standardization and are used in a variety of circumstances typical of literary languages—albeit in a limited fashion and always alongside a national literary language.
Native speakers (or users) of contemporary Slavic microlanguages either live among unrelated linguistic communities, thereby constituting an ethnic "island", or live on the geographical of their historical ethnic group. Correspondingly, these microlanguages can be divided into insular and peripheral categories (the latter of which can also be called "regional languages"). The principal insular forms are: Rusyn, Burgenland Croatian, Molise Croatian, Resian dialect (which may also be characterized as "peninsular") and Banat Bulgarian. The main peripheral forms include Prekmurje Slovene, East Slovak, Lachian, Carpatho-Russian, West Polesian and others.