Conlang vs. Natlang

Conlang and Natlang Definitions
Conlang
Alternative form of constructed language
Natlang
A natural language, one that arose without intentional design.
Proto-Indo-European was a natlang that can only be reconstructed with the help of its attested daughter languages.
Conlang
To create or work on a conlang (constructed language).
The conlanging community
Brithenig was conlanged with the purpose of looking how Welsh might have developed if it were a Romance language.