The discipline of silence doesn't mean just taking a short vacation from the spoken word. It also means giving complete relaxation to the muscles, the tissues, the tongue itself. A modern writer once said: "Knowledge has never been known to enter the head via an open mouth." It is when you become completely silent that you are able to absorb knowledge. God speaks in silence. The discipline of silence is essential on the path.
Dom Henri le Saux, a French Benedictine monk, suggests that the sacred sound "OM" can be used by anyone:
More than any particular name of Divinity, OM conveys the ineffability and the depths of the divine Mystery. It bears no distinct meaning ... It does not even recall any mythological or semi-historic event. It is a kind of inarticulate exclamation uttered when you are confronted with the Presence in yourself and around yourself.
You could say that OM is a name of God which is not a name.