Angels are spirits and spiritual activity by its nature is silent because its does not have a body or interactive parts but only the dynamics of intellect and free will.

First, of all angels came forth from God with silent minds. They are created with intuitive knowledge and wisdom pertaining to their sphere of action. As the human eye sees all that is before it at a glance, so to the angelic mind the whole field of science is open to its perception. For example, "An angel concerned with our planet earth would have a Gaian sphere of action, and a unified knowledge of what is going on on earth." (Matthew Fox & Rupert Scheldrake, The Physics of Angels, Harper San Francisco, 1996, p.113) According to the Gaian hypothesis, "The earth is a self-regulating environment and the planet itself is the core of a single, unified, cooperating and living system -- a superorganism that regulates physical conditions to keep the environment hospitable for life forms". (Website: Earth 2: The Gaia Hypothesis) While there is some truth in this hypothesis, to make the earth conscious and intelligent in its totality is a myth. However, if we envisage angelic minds in this process, it would make sense. Angels are persons with intelligence loving power who can easily act upon self-organizing fields, such as gravity, electromagnetism and the fields of living organism thus regulating the life sustaining processes we observe. "Being entirety free of passions and all sensitive appetites , the act of the Angelic will is determined exclusively by the Angelic mind with a decision and firmness that are final and admit of no reverse." (Paschal P. Parente: The Angelic Nature and its Operation, ch.2)

Angels communicate with one another but do not do so in words because they have no bodies. When we talk to one another we used words, actions or other symbols (e.g. writing) which cannot fully convey our concepts. Angels, on the other hand, convey crystal clear ideas directly to other angels by opening up their minds and revealing whatever ideas they wish to convey to other angels. This is the language inherent in their nature with which they were created with and so do not have to learn a language. This is a very silent way to communicate. Angels can, however, adapt their mode of communication in order to be seen and heard by men as scripture relates. How they manage this we do not know. This is not part of their nature but would be like us appearing to be different by wearing facial flexible masks and different clothes. In demonic possession we see that they are capable of taking over human functions in order to speak with a human voice.

We usually visualize angels as having wings which symbolize their freedom of movement. Actually they move as the speed of their thoughts and are instantly where they choose to act. We can only travel in this way mentally. For example, I can visualize myself as being on Mars but cannot do anything there because my body is on earth. Since the angel's way of movement is not by passing trough a space-continium, they make no sound and we cannot hear them.

We must also remember that the angels continually behold the face of God as Christ tells us, "See that you do not despise one of these little ones, for I say to you that their angels in heaven always look upon the face of my heavenly Father." (Mt. 18:10). Standing always before the Holy deepens their silence in wonder and joy which does not detract from their role as creatures as work in God's creation. We are not fully able to do this as we can see by the division of religious life into the Contemplative and Active orders.