וּלְבַ֥ב נִמְהָרִ֖ים יָבִ֣ין לָדָ֑עַת וּלְשׁ֣וֹן עִלְּגִ֔ים תְּמַהֵ֖ר לְדַבֵּ֥ר צָחֽוֹת׃
The heart also of the rash shall understand knowledge, And the tongue of the stammerers shall be ready to speak plainly.
Read kabbalistic (mystical) interpretation of Isaiah 32:4: and classical mystical sources.