Invented languages have often been created in tandem with entire invented universes, and most conlangers come to their craft by way of fantasy and science fiction.

Foer is observing a common pathway into constructed languages (conlangs): they frequently arise as part of larger acts of world-building. Rather than being invented purely for linguistic experiment, many conlangs are designed to make fictional cultures feel lived-in—complete with history, social structure, and aesthetic texture. The second clause generalizes about the conlang community: many practitioners are drawn from fantasy and science fiction fandoms, where languages function as a hallmark of depth and authenticity (e.g., Tolkien’s model). The quote also hints at a feedback loop: imaginative universes motivate language creation, and the language in turn enriches and stabilizes the imagined universe.