I haven't played this game either, but I heard that these strange words can be found in the hidden room of the screening room in the game(I'm not sure what English will translate into, maybe it's a place where you can watch videos or something like that?) as a comparison to Japanese 50 tone(日语50音/ごじゅうおん)
This answer comes from 2016, and like the official text above, mentions the "死灵之书(Necronomicon) ",so I think this answer may be related to this question