Inter-Slavic language is a language understandable to all Slavs without learning.
The language under the name “Medžuslovjansky jezik” was officially created in 2017 by merging the projects of Czech university professor Vojtěch Merunka and Dutch translator Jan Van Steenbergen.
Flag of the Inter-Slavic language

The official flag of the Inter-Slavic language
The inter-Slavic language is a semi-constructed language, created by processing and modernizing the Church Old Slavonic language - the first written language of all Slavs.
The Old Church Slavic language is closely related to the missionary work of Cyril and Methodius, who created the first Slavic script - the Glagolitic script.
The first grammar that unites all Slavic languages was written down by none other than the Croatian priest Juraj Križanić, known today as the first documented bearer of the Pan-Slavic idea.
The inter-Slavic language has a lively and active community that counts tens of thousands of active members of various levels of language use. A native speaker of a Slavic language can master an inter-Slavic language in a short period of time, and with good instruction can also understand other Slavic languages. You can find inter-Slavic language lessons here.
The inter-Slavic community has its own cultural production - its songs, stories, films and events with the aim of developing the inter-Slavic language and cultural exchange.
The Association of Inter-Slavic Culture is the first formal organization in Croatia and in the world with the aim of developing the inter-Slavic language of its community.
More about us.