From D&D Wiki
The language spoken by the Yōkai peoples, it sounds very alien and is impossible for most races to speak, because it does not use humanoid vocal cords to produce the sounds needed to speak it. It sounds like a large tree creaking, with deep sounds clicks and almost arcane noises with a more humanoid layer of sounds over the top of this. It does not have a written script, but it is printed using woodblock. It uses a Logographic script when printed, with straight lines with breaks, similar to morse code wrapping around the logographic forms to represent the deeper guttural sounds, making up grammar, tone, and context.