The story
The noun is a syllabic abbreviation of constructed language, while the verb is derived from the noun. By surface analysis, con- (“constructed”) + lang or -lang (“language”).
First known use, by meaning
- from 1990s Alternative form of constructed language (“a human language consciously devised by an individual or a small group, as opposed to having naturally evolved as a natural language”)
Etymology from Wiktionary, CC BY-SA 4.0.