It is essentially a modern continuation of Old Church Slavonic, but also draws on the various improvised language forms that Slavs have used for centuries to communicate between nationalities, for example in multi-Slavic environments and on the Internet, providing them with a scientific base.

Its main focus lies on instant intelligibility rather than easy learning, a balance typical for naturalistic (as opposed to schematic) languages.

In 2011, Slovianski underwent a thorough reform and merged with two other projects, with the result called "Interslavic", a name that was first proposed by the Czech Ignác Hošek in 1908.

Precursors of Interslavic have a long history and predate constructed languages like Volapük and Esperanto by centuries: the oldest description, written by the Croatian priest Juraj Križanić, goes back to the years 1659–1666.

However, the role of the Russian language as a lingua franca in Eastern Europe and the Balkans diminished after the collapse of the Soviet Union.

In March 2006, the Slovianski project was started by a group of people from different countries, who felt the need for a simple and neutral Slavic language that the Slavs could understand without prior learning.

Apart from these two variants (N stands for naturalism, P for pidgin or prosti "simple"), a schematic version, Slovianski-S, has been experimented with as well, but was abandoned in an early stage of the project.

Although Slovianski had three genders (masculine, feminine, neuter), six cases and full conjugation of verbs—features usually avoided in international auxiliary languages—a high level of simplification was achieved by means of simple, unambiguous endings and irregularity being kept to a minimum.

[14][15] In February and March 2010 there was much publicity about Slovianski after articles had been dedicated to it on the Polish internet portal Interia.pl[16] and the Serbian newspaper Večernje Novosti.

[17] Shortly thereafter, articles about Slovianski appeared in the Slovak newspaper Pravda,[18] on the news site of the Czech broadcasting station ČT24,[19] in the Serbian blogosphere[20] and the Serbian edition of Reader's Digest,[21] as well as other newspapers and internet portals in the Czech Republic, Slovakia, Hungary, Serbia, Montenegro, Bulgaria and Ukraine.

[33] In 2009 a new language was published, Neoslavonic ("Novoslovienskij", later "Novoslověnsky") by the Czech Vojtěch Merunka, based on Old Church Slavonic grammar but using part of Slovianski's vocabulary.

[13] Slovianski grammar and dictionary were expanded to include all options of Neoslavonic as well, turning it into a more flexible language based on prototypes rather than fixed rules.

From that time, Slovianski and Neoslavonic have no longer been developed as separate projects, even though their names are still frequently in use as synonyms or "dialects" of Interslavic.

An early example of this endeavor is Merunka and van Steenbergen's joint publication on Slavic cultural diplomacy, released to coincide with the conference.

[39] The number of people who speak Interslavic is difficult to establish; the lack of demographic data is a common problem among constructed languages, so that estimates are always rough.

[48] The project has two online news portals,[49][50] a peer-reviewed expert journal focusing on issues of Slavic peoples in the wider sociocultural context of current times[51] and a wiki[52][better source needed] united with a collection of texts and materials in Interslavic language somewhat similar to Wikisource.

[54] In June 2017, the first CISLa (Conference on InterSlavic Language) took place in the Czech town of Staré Město near Uherské Hradiště.

They differ from the standard orthography by carrying a diacritic which conveys etymological information linking directly to Proto-Slavic and Old Church Slavonic (OCS).

The consonants ď, ľ, ń, ŕ, ś, ť and ź are softened or palatalized counterparts of d, l, n, r, s, t and z.

[65] Cyrillic equivalents of the etymological alphabet and ligatures can also be encountered in some Interslavic texts, though such spelling is not officially sanctioned.

[68] Interslavic grammar is based on the greatest common denominator of that of the natural Slavic languages, and partly also a simplification thereof.

Nouns can have three genders, two numbers (singular and plural), as well as six cases (nominative, accusative, genitive, dative, instrumental and locative).

These verbs are formed regularly: Some aspect pairs are irregular, for example nazvati ~ nazyvati "to name, to call", prijdti ~ prihoditi "to come", podjęti ~ podimati "to undertake".

Often used are the following alternative forms: A few verbs have an irregular conjugation: Words in Interslavic are based on comparison of the vocabulary of the modern Slavic languages.

Prvy tegal težky voz, vtory nosil veliko brěme, tretji brzo vozil muža.

Ovca rěkla konjam: «Boli mně srdce, kogda vidžu, kako člověk vladaje konjami.» Konji rěkli: «Slušaj, ovco, nam boli srdce, kogda vidimo ovo: muž, gospodar, bere tvoju volnu, da by iměl dlja sebe teplo palto.

Првы тегал тежкы воз, вторы носил велико брєме, третји брзо возил мужа.

Овца рєкла коњам: «Боли мнє срдце, когда виджу, како чловєк владаје коњами.» Коњи рєкли: «Слушај, овцо, нам боли срдце, когда видимо ово: муж, господар, бере твоју волну, да бы имєл дља себе тепло палто.