Like reading, prayer can be silent. Hannah, who longed for a child of her own, visited the temple and "spoke in her heart" as she prayed. Her lips were moving, but "her voice was not heard" (1 Sam. 1:13). Eli the priest saw but misunderstood what was happening. She explained, "I have poured out my soul before the Lord" (v. 15). God heard Hannah's silent prayer request and gave her a son (v. 20).
Since God searches our hearts and minds (Jer. 17:10), He sees and hears every prayer - even the ones that never escape our lips. His all-knowing nature makes it possible for us to pray with full confidence that He will hear and answer (Matt. 6: 8, 32). Because of this, we can continually praise God, ask Him for help, and thank Him for blessings - even when no one else can hear us. God fills our heart with peace when we pour out our heart to Him.