To pray a personal prayer to God. The recommended way of the Lord Jesus Christ if you're to pray alone is to pray secretly.
Matthew 6:5-6 KJV
This is recommended when praying alone. You can pray in secret.
1 Corinthians 14:15 KJV
You can pray to God without saying a word. Do not do as the Greeks do while praying, they show themselves to people just to appeal and show off.