Rubrics are directions or explanatory instructions printed in between prayers or other texts of a liturgical rite. The word “rubric” is derived from the Latin word for red “ruber”, since they are normally printed in red in the liturgical books.
In this case, it has in red: “Next the priest stands at the side of the altar and washes his hands, saying inaudibly:” Then in black it has: “Lord, wash away my iniquity; cleanse me from my sin.”
The 2002 Roman Missal’s Latin text in red is: “28. Deinde sacerdos, stans ad latus altaris, lavat manus, dicens secreto:”
Does “dicens secreto” mean “says inaudibly”? The approved translation for the USA of the 2002 General Instruction of the Roman Missal (GIRM) has “145. After the prayer In spiritu humilitatis (Lord God, we ask you to receive us) or after the incensation, the priest washes his hands standing at the side of the altar and, as the minister pours the water, says quietly, Lava me, Domine (Lord, wash away my iniquity).” Here “secreto dicens” has been translated as “says quietly”.
So its reasonable to hear the words, but they should be the correct ones, following the 2004 Instruction Redemptionis Sacramentum: “[59.] The reprobated practice by which Priests, Deacons or the faithful here and there alter or vary at will the texts of the Sacred Liturgy that they are charged to pronounce, must cease. For in doing thus, they render the celebration of the Sacred Liturgy unstable, and not infrequently distort the authentic meaning of the Liturgy.”
References:
Dennis Smolarski, Liturgical Literacy, Paulist Press, 1990, ISBN 0-8091-3137-4, page 180.
The Roman Missal, Catholic Book Publishing Co., New York, 1985, page 371.
Missale Romanum, Libreria Editrice Vaticana, 2002, ISBN: 8820972719, page 515.
The 2002 GIRM can be accessed from
romanrite.com/girm.html