Zonal constructed languages are constructed languages made to facilitate communication between speakers of a certain group of closely related languages. They form a subgroup of the international auxiliary languages, but unlike languages like Esperanto and Volapük they are not intended to serve as languages for the whole world, but merely for a limited linguistic or geographic area. While there is some overlap with the term "Euroclone", the latter usually refers to languages intended for global use but based exclusively on European material. Another related concept is known as a koiné language, a dialect which naturally emerges as a means of communication among speakers of divergent dialects of a language. Most zonal constructed languages were created during the period of romantic nationalism at the end of the 19th century, but some were created later. Nowadays, most older zonal constructed languages are known only to specialists. Modern examples are Interslavic and Folkspraak.
Pan-Slavic languages
Most numerous within this category by far are Pan-Slavic languages. The oldest known example is Ruski jezik by the Croatian priest Juraj Križanić, who is often regarded as the first recorded Pan-Slavist. Other notable examples of early Pan-Slavic language projects are Universalis Lingua Slavica by Ján Herkeľ, Uzajemni Pravopis Slavjanski by the Slovene Matija Majar, Neuslawisch by the Czech Ignac Hošek and Slavina by the Czech Josef Konečný. Until the beginning of the 20th century, all projects were characterized by a heavily naturalistic grammar, based directly or indirectly on Old Church Slavonic. Their authors were motivated by the belief that all Slavic languages were dialects of one single Slavic language rather than separate languages. They deplored the fact that these dialects had diverged beyond mutual comprehensibility, and the language they envisioned was intended to reverse this process. Their long-term objective was that it would replace the individual Slavic languages. Naturalistic projects have been created later as well. Notable examples are Mežduslavjanski jezik, an unpublished project from the years 1954–1958 by a team of Czech interlinguists, including Ladislav Podmele; Slovianski, a collaborative project started in 2006; and Novosloviensky, based on Old Church Slavonic and published in 2010 by the Czech Vojtěch Merunka. In 2011, Slovianski and Novosloviensky merged into one common project under the name Interslavic, also incorporating material from older naturalistic projects. Most naturalistic projects are so similar that they can easily be considered versions of the same language. During the 20th century, however, a few schematic projects have emerged as well, such as Slovanština, Neposlava, Slavski jezik and Slovio. These projects aim at radical simplification of the grammar, often combining Slavic vocabulary with Esperanto grammar.
Pan-Germanic languages
Languages for Pan-Germanic use have been created as well. Known examples are Tutonish, a Pan-Germanic project by Elias Molee, which was intended to be an auxiliary language at first but to eventually supplant all other Germanic languages, Euronord for Northern Europe by A.J. Pilgrim and Folkspraak, a heterogeneous project consisting of various dialects, started in 1995.
Pan-Romance languages
Many international auxiliary languages intended for global use consist exclusively or predominantly of Latin and/or Romance material, like Latino sine flexione, Neolatino by André Schild, Internacional by João Evangelista Campos Lima, Interlingua, by David Th. Stark and Lingua Franca Nova, which makes it hard to distinguish them from Pan-Romance languages. Some languages, however, have been presented explicitly as languages for use among Romance speakers, for example Romanid, by David Crandall and Robert W. Hubert, by Richard Sorfleet and Josu Lavin, by a group of linguists led by Jordi Cassany Bates and by Raymund Zacharias and Thiago Sanctus.
Other zonal constructed languages
Apart from these European examples, there have also been attempts on other continents:
