The Mass is principally a Sacrifice, for Christ, after declaring and effecting that bread and wine become "My Body given for you... My Blood poured out for you..." (thus making present His bloody Sacrifice on Calvary), commanded His disciples (ipso facto ordained priests of the New Testament) to "Do this in memorial of Me". Note they were told to Do, not Say.
Since the Mass is fundamentally a Sacrifice, what is important is what is done - not what is said. It is so obvious, really, that, while words are employed, the prayer of the priests is their liturgy and duty, and the hearing of it by the faithful is not necessary - what is necessary is that the faithful know, believe in and unite themselves to the Mystery being enacted, to the offering up of the One Sacrifice, praying the Mass. As the mediæval canonist Lyndwood put it, the Canon of the Mass is silent ne impediatur populus orare - that the people be not hindered from praying.
A nice reflection about Sacrifice from another blog some time ago also let me in on a useful parallel to the exordium Vere dignum of the Preface, and the initial prayer to bless the sacrifice in Te igitur (which I would add also parallels the intercessions of In primis and Memento Domine): in I Machabees i, 24-29, Nehemias is pictured as offering a prayer of his own at the time when "all the priests made prayer while the sacrifice was consuming..." (verse 23):
O Lord God, Creator of all things, dreadful and strong, just and merciful, who alone art the good kind, who alone art gracious, who alone art just and almighty and eternal, who deliverest Israel from all evil, who didst choose the fathers and didst sanctify them:Receive the sacrifice for all thy people Israel, and preserve thy own portion, and sanctify it.Gather together our scattered people: deliver them that are slaves to the Gentiles and look upon them that are despised and abhorred: that the Gentiles may know that thou art our God. Punish them that oppress us, and that treat us injuriously with pride. Establish thy people in thy holy place, as Moses hath spoken.