Lady, EVOLVED 
according to the dream i just woke up from, the gold standard elementary text for translating into your conlang should be “peter and the wolf”
Wikipedia claims peter and the wolf was formerly in the public domain but placed back under copyright by Golan v. Holder—who is the copyright holder tho?
it was commissioned by a childrens theatre run by the Soviet government
@Lady Arguably the theatre or any successors, or possibly just an orphaned work? (Peter Pan, the play, is my favorite "what is even going on?" children's story for licensing weirdness. Woe betide anyone trying to do something with it in the UK, or the US until recently.)
@aschmitz it’s very interesting because every article about Golan v. Holder explicitly talks about Peter and the Wolf no longer being public domain, but none of them identify any party who actually has the ability or motivation to levy a copyright infringement lawsuit
presumably there is someone, but it just goes to show in a sense how people think about these things (wrongly, imo)
@Lady I suspect that in general we just haven't really figured out what to do with "orphaned works" in general: they're theoretically copyright even though nobody actually controls that right. (You can of course argue about whether that means they actually are or not: either way the effect is the same as if they are not, but it is hard if not impossible to be sure that they actually aren't controlled.)
@aschmitz this is definitely true (us not knowing how to deal with orphaned works), but an essential component is how it intersects with fair use: if there is no known copyright holder, it's going to be very hard to claim that a nonprofit transformative use of a work is unfairly infringing (i am not a lawyer and this is a layman’s opinion)
the major liability is in the case that a known copyright holder emerges and decides to pursue their copyright claims: then anything you might have produced using the work might cease to be a fair use and might start being infringing. this is an undue risk for any large-scale operation, probably, but likely not for something hobbyist and indie (this is a personal opinion and not legal advice)
@aschmitz and not always favouring the corporations!