Mythical creatures could be considered to be children of the Dao which gave them absurd power to the point they could bend the world around them through the power of their tongues.
Mastering their language, equated to mastering a part of their abilities related to which tongue you had mastered.
Learning the language was hard enough even just at the beginner level was as hard as mastering a gold-grade cultivation art to the emergent level, and then came another problem, executing the art.
For the language to reach its full potential, one needed a body that was endowed like a mythical creature. If their body was in any way lacking, they invited risks when executing the art, such as being consumed by the art when learning it or when executing, and if they had enough tenacity to push through without having a mythical creature's body, they still suffered a tremendous backlash on their bodies to release it.
