妙法蓮華經玄義 8.39

8.39

心是法本者，《釋論》云：「一切世間中，無不從心造」，無心無思覺，無思覺無言語，當知心即語本。

As for the mind being the root of dharmas, the Commentary says: "In all the world, there is nothing that is not created from the mind." Without mind, there is no coarse examination or subtle investigation; without coarse examination or subtle investigation, there is no speech. One should know that the mind is the root of speech.