Mind is subtler than speech: contemplate on what you think, why you think, and how your thoughts affect your speech and actions. If you cannot quiet the mental noise, then fill your mind with Brahman consciousness.
While trying to understand your mind and attempting to fill it with Brahman consciousness, you will notice an even subtler force called samkalpa, the power of determination.
The mind cannot think unless you decide what it will think. At your behest, your mind thinks, and only when your mind thinks do the words come forward. The power of determination, which is a subtle desire springing from the core of your being, is the driving force behind the activities of your mind.
(Source: The Tradition of the Himalayan Masters by Pandit Rajmani, Ph.D.)