Movement of Tongue
One’s tongue moves according to the fixation of his mind. Always think of Krishna, then you can’t help but speak of your beloved Lord.
Prajalpa
One should avoid prajalpa, talking of mundane subject matter, unrelated to devotional service.
Speech of A Pure Devotee
When a pure devotee or spiritual master speak, what he says should be accepted as having been directly spoken by the Supreme Personality of Godhead in the Parampara System. — Sri Caitanya Caritamrita, Antya Lila, 05.71.
Actual Speech
Actual speech is that which describes the qualities of the Lord, real hands are those that work for Him, a true mind is that which always remembers Him dwelling within everything moving and nonmoving and actual ears are those that listen to sanctifying topics about Him.
Speech of A Pure Devotee or Spiritual Master
When a pure devotee or spiritual master speaks, what he says should be accepted as having been directly spoken by the Supreme Personality of Godhead in the Parampara system.
Speech
Speech is the power of Krishna, therefore we have no right to misuse it.