When we are full of joy and gratitude to God, we talk with Him in praises, psalms and songs. “Speaking to yourselves in psalms and hymns and spiritual songs, singing and making melody in your heart to the Lord,” Ephesians. 5:19.
We also communicate with God by our behaviors. Perhaps you’ve heard the saying, “Your actions speak louder than your words.” So every time we engage in study, in witnessing, in helping our brethren and blessing our neighbors, we are speaking to God. We are telling Him we love to obey His will.
Additionally, there are times when it is difficult to relate our deep feelings with words of prayer. Perhaps we are experiencing great grief, pain, or anxiety. Then we talk to the Lord with our quiet sighs, which God understands. “…the spirit (our our spirit) joins also its help to our weakness; for we do not know what we should pray for as is fitting, but the spirit (our spirit) itself makes intercession with groanings which cannot be uttered,” Romans 8:26 (DBY).