They form a subgroup of the international auxiliary languages but are intended to serve a limited linguistic or geographic area, rather than the whole world like Esperanto and Volapük.
Until the beginning of the 20th century, all projects were characterized by a heavily naturalistic grammar, based directly or indirectly on Old Church Slavonic.
They deplored the fact that these dialects had diverged beyond mutual comprehensibility, and the language they envisioned was intended to reverse this process.
During the 20th century, however, a few schematic projects have emerged as well, such as Slovanština (Edmund Kolkop, 1912), Neposlava (Vsevolod Cheshikhin, 1915), Slavski jezik (Bohumil Holý, 1920) and Slovio (Mark Hučko, 1999).
[citation needed] 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 (1947), Internacional by João Evangelista Campos Lima (1948), Interlingua (IALA), Latino Moderne by David Th.
Some languages, however, have been presented explicitly as languages for use among (or with) Romance speakers, for example Romanid, Romanova by David Crandall and Robert W. Hubert (2000), Interlingua Romanica by Richard Sorfleet and Josu Lavin (2001), Romance Neolatino by a group of linguists led by Jordi Cassany Bates (2012) and Latino Interromanico by Raymund Zacharias and Thiago Sanctus (2017).