Prayer is an act of love; words are not needed. Even if sickness distracts from thoughts, all that is needed is the will to love.
It is of great importance, when we begin to practise prayer, not to let ourselves be frightened by our own thoughts.
They deceive themselves who believe that union with God consists in ecstasies or raptures, and in the enjoyment of Him. For it consists in nothing except the surrender and subjection of our will - with our thoughts, words and actions - to the will of God.