Plato’s Sound Language against the Harm done to Language

“To speak in a harmful way (τὸ μὴ καλῶς λέγειν) is not only a false note towards language itself (εἰς αὐτὸ τοῦτο πλημμελές), it is also to infuse some evil within souls.” This worrisome statement in the Phaedo (115 e 5–7) should be considered as a key of Plato’s dialogues. But how shall we understand the harmfulness of a “false note” inside the very language thought of as having its own autonomy? Does it have to do with “stasis between names” (Cratylus 438 d 2), and if so, where to find, inside language, the “right note” capable of preventing the disaster of souls?