Dear Betsy:

Sorry for the delay in answering.

Praying out loud is efficacious to our faith because it involves multiple senses. God made us sacramental people. That means that He made is to relate to the world through our senses. This is one reason the Church as all the "smells and bells", liturgical colors, etc.

When we read out loud we involve thought, the physical formation of words through our larynx , the sound of the word, which we hear with our ears.

But, as for prayers said out loud as being more powerful, that is not necessarily true. In deliverance counseling we often say prayers under our breath or silently in our minds when a client is being attacked as he is saying a deliverance prayer. Demons cannot read our minds, but we are directing our silent deliverance prayer to the demons to rebuke the demon. They hear this. We advice our clients to rebuke demons whenever they attack. If they attack when the person is in a public setting, we tell them to rebuke the demons silently in there minds.

Thus, when you cannot say a prayer out loud, say it silently in your mind. The demons will hear the rebuke. Demons cannot read our minds, but we can willingly direct our thoughts (prayers of rebuke) to them.

God Bless,
Bro. Ignatius Mary