Silent prayer is not a thought prayer. Silent prayer for us Jews- The Amidah, is when I verbalize this prayer so that only I can hear it.
The Amidah is action through speaking. It is an undertone. Only I and G-d hear this prayer.
This silent prayer is taken from Chana’s prayer. She is the mother of Samuel. The prophet describes the prayer to G-d to merit the birth of a child. “As she kept on praying before the L-rd, Eli watched her mouth. Now Hannah was praying in her heart; only her lips moved, but her voice could not be heard. So Eli though she was drunk.”
Imagine standing before G-d without too much emotion verbalizing the words of prayer.
This is final rung of prayer.
I am standing before G-d speaking before my master.
I am speaking directly to G-d.