God knows our hearts and our prayers. We do not know precisely how, as we are incapable of knowing - being mere creatures. The Archangels (Book of Tobit) and Saints (Revelation 5), carry our prayers to the throne and present them to the Father. This we know specifically.
Personally, one of the most powerful prayer experiences I have ever known involved not a single word. Just tears before Christ in the Blessed Sacrament. It was that occasion in which I specifically received the consolation of the Holy Spirit. Words cannot describe it.