Liturgy is NOT just the Mass.  There is the praying of the Liturgy of the Hours[Divine Office of the Church].  In the Constitution on the Sacred Liturgy [84], it is stated that the Second Vatican Council showed the importance of the traditional discipline of the Church and desired to renew that discipline.  It was very concerned to bring about a suitable restoration of this liturgy of prayer so that priests and other members of the Church in today's circumstances might celebrate it better and more effectively.

If non-clergy are invited to pray the Liturgy of Hours---there is nothing to prevent them from fuller participation in the Eucharistic prayer---as Loy and spiretsma29 attest.