By observing silence, you can attain some degree of control over your speech, but this will not bring you peace and happiness. Once the disturbance at the level of speech is quieted, you will notice unexpected turbulence in the mind.
In order to attain peace, you must work systematically. First, bring peace to your tongue. This means speaking sweetly and making sure that you do not harm either yourself or others through your speech.
Avoid meaningless talk. This observance will lead you to mental peace.
By observing this discipline of speech, you maintain awareness of Brahman – the highest truth.
Source: The Tradition of the Himalayan Masters Pandit Rajmani, Ph.D. Tigunait