At a certain pitch of religious experience, the heart just wants to sing; it breaks into song. Paradoxically, you could say when silence finds its fullness, it comes to word. As the Book of Wisdom says, "When night in its swift course had reached its halfway point and deep silence embraced everything" -- when night was at its darkest and deepest -- there "the eternal Word leaped from the Heavenly throne": silence burst into song.
Mystical wisdom derives from an ardent desire to abandon normal intellectual functions so that divine insight may enlighten this ardor and add to it another fire, much stronger, which lifts the burning soul towards an even deeper wisdom.