Naturalistic planned language

A naturalistic planned language is an a posteriori constructed language specifically devised to reproduce the commonalities in morphology and vocabulary from a group of closely related languages, usually with the idea that such a language will be easier to use passively – in many cases, without prior study – by speakers of one or more languages in the group. The term most commonly applies to planned languages that are predominantly based on the Romance languages, best known of which are Interlingue (previously known as Occidental) and Interlingua.

Source: Wikipedia — Naturalistic planned language (CC BY-SA 4.0)