> Does this mean that it is futile or meaningless to attempt to compose Elvish sentences? Well, no. [...] it is indeed possible to produce written Elvish that so far as anyone now can tell conforms grammatically and idiomatically to the exemplars and statements that Tolkien provided to a very high degree (for example, by relying only upon attested elements and derivational mechanisms, attested grammatical devices, and attested syntactic patterns that can reasonably be thought to belong to the same conceptual phase) — though I very much doubt that anyone will ever be able to do so quickly enough to use Elvish as a spoken language, for any but the most trivial sorts of declarative sentences.

I hate to be the one, but I haven't seen anyone else refer to them: how good are LLMs at following patterns of invented languages, in either direction (ie. inventing a translation from English to Sindarin and then, separately, translating the invented Sindarin back to English)? It's a usage where "hallucinations" are basically required, but also, the consistency of hallucinations has to be high.