"When you pray, go into your room, close the door and pray to your Father, who is unseen. Then your Father, who sees what is done in secret, will reward you. And when you pray, do not keep on babbling like people think they will be heard because of their many words. Do not be like them..." Jesus, Matthew 6:6-8
Silent prayer is how we cultivate sensitivity, receptivity, and a sincere consent to God's abiding love and presence.
When we don't stop talking or acting, our focus quickly becomes fundamentally (yet, innocently) self-centered because our prayer is driven by feelings, impressions, and desires and our ability to articulate them. This naturally veers our attention toward how we feel about God, what we want from God, or what we want God to change. Those aren't bad things, but they are each centered around ourselves (self-centered).
Letting silence be a prayer language is a way of learning to let God to be God as God is and you to be you as you are. It is consenting to a trust that God does not need to be or do anything more than He already is and is doing. And that He loves us as we are and not as we should be (to quote the great Brennan Manning). God is Good. God is Love. Does He need to prove it through our circumstances before we choose to just accept Him in the same way that He accepts us?
"...you are worried and upset about many things, but few things are needed—or indeed only one." Jesus, Luke 10:41&42