if we are getting specific... they are our descendants from a potential timeline, thousands of years in the future. they live on another planet, and do have their own language, with some of its ancient roots in our own language.

not actually a potential timeline, since they did not experience that kind of contact with themselves.... our own potential futures are potentially even brighter than this already very positive civilization. but they serve as a fine example.

the method of communication provides its own translation, so their language isn't really encountered except through specific discussion. also, they have been strongly telempathic for many generations, so written and spoken language is pretty archaic and irrelevant to them.

the communications from that one particular source have been going on for 40 years, but there are other sources with overlapping information.

yeah he's been going for 40 years, but a few years back he produced a documentary. it makes a good introduction. here it is https://m.youtube.com/watch?v=51NngCeGCKo