On Sundays my priest usually reads the silent prayers aloud. The people bow at the waist at "take, eat...", "drink of it all of you...", "make this bread...", " and that which is in this cup..." and "changing them by the Holy Spirit." The last three are ended by "Amen" (the last one a triple "Amen") and those in the altar prostrate after the last of the triple "Amen"s. The last three are occuring at the same time as "We Praise Thee" is sung by the choir, which they start immediately after "Thine Own of Thine Own..."
On weekday Liturgies, however, our priest is more likely to say the prayers silently.