Lost to who? Ask the locals and they'll know all about it.
Reminds me of this story (here simplified and from memory :-) about ancient Maya script that was deciphered once the brilliant code breakers had the inspiration to talk to the locals (who were still talking the script)
If you’re interested, a great popular account is given in Micheal Coe’s book Breaking the Maya Code or you can read an interview with David Stuart, who started work on Maya writing when he was ten! https://nightfirefilms.org/breakingthemayacode/interviews/St...
The low hanging fruit is picked.