This podcast is a reading from the collected works "Theology of the Liturgy" by Cardinal Josef Ratzinger.
It is a follow up to the podcast "Love and Worship" because it gives a wider and deeper understanding of what it means to participate in the sacred liturgy, the Holy Mass. Although he writes theologically, I have always found our Pope Emeritus to be singularly clear in his thought and in his expression.
Some Latin words that he uses might be helpful to see:
actio is the origin of our English action
oratio is the origin of our English oration but sometimes it is translated as prayer, though there is another Latin word prex which means prayer or intercession.