Summary based on Catechism paragraphs 2700-04:
We are most familiar with vocal prayer, for it involves words, whether spoken aloud or thought silently. It is the most common expression of prayer because it fits our human nature so readily.
We are endowed with the gift of communicating by means of language, and God has revealed Himself to us through His Word. Giving voice to our prayer is likewise completely natural for us: composed of both body and soul, we want to involve our entire being, all of our senses, in the act of praying.
Jesus engaged in vocal prayer throughout His earthly life, in His personal prayers to the Father as well as by participating in communal worship in the synagogue, and He taught us the perfect vocal prayer, the “Our Father.”
But perhaps because we have memorized certain prayers, we can find it very easy to lapse into auto-pilot mode, and recite the words mechanically. While that qualifies as “vocal,” it doesn’t rise to the level of “prayer” unless our minds and hearts are truly lifted up to the Lord.
When we teach our little ones how to say their prayers, let us also remind them – and ourselves – that we are literally speaking to God. This becomes much easier if we place ourselves in His presence before beginning to pray.