Likutei Moharan 212:4/ליקוטי מוהר"ן רי״ב:ד׳

14. The power of speech comes from attachment to the tzaddikim, as is brought (Tikkuney Zohar #18, p.32b): It is called “mouth” by virtue of the tzaddik.

2(From Lesson #208 until here is leshon Rabbeinu .)