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 periphery 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.
The precise hierarchical relationship between national literary languages and microlanguages can be ascertained by examining internal attributes, such as the disparity between strictly enforced standardization in the case of the former and, in the case of the latter, a more relaxed standard. The national language often displays a standardized spoken form whereas such a regularity is absent from microlanguages (whose spoken form often consists of divergent dialects.) Likewise, the difference can be seen in external attributes such as extensive functionality and explored genres in the case of national languages, compared to the narrowness of genres and limited functional role of microlanguages.
As literary microlanguages are, in terms of functionality, more expansive than their corresponding dialects, they display a tendency toward standardized norms, which entails a significant enlargement of the lexicon and a more systematized, codified grammar, often by way of foreign borrowings, and recourse to a previous literary and linguistic tradition alien to dialects. In contrast to a dialect exploited for artistic purposes, every minor literary Slavic language is to a greater or lesser degree governed by an organized literary and linguistic process that provides for the establishment and development of a literary microlanguage, and which presents it as such.
In terms of location, Slavic microlanguages exist in both predominantly Slavic and non-Slavic areas, earning some the designation of linguistic "islands" resulting from a past migration, whereas others exist indigenously, having never been entirely separated from their genetic and geographic points of origin.