I think of the movies of olden times where you might see a subject who, on bended knee before his lord, master or king, put is fist on his breast as an act of allegiance
We always did this pre-Vatican II days at Mass. Maybe see Luke 18:13?
Douay-Rheims Bible:And the publican, standing afar off, would not so much as lift up his eyes towards heaven; but struck his breast, saying: O God, be merciful to me a sinner.
Also, we were taught to do this when praying the Salve Regina:Hail Holy Queen, Mother of Mercy, our life our sweetness and our hope. To thee do we cry, poor banished children of Eve; To thee do we send up our sighs, mourning and weeping in this vale of tears. Turn then, most gracious advocate, thine eyes of mercy toward us and after this our exile show unto us the blessed fruit of thy womb, Jesus. O clement, O loving, O sweet Virgin Mary!
V- Pray for us, O Holy Mother of God
R- That we may be made worthy of the promises of Christ.
We would strike our breasts once at each āOā exclamation after the name of Jesus.
I remember asking my dad, āWhat does āvaleā mean?ā Growing up Catholic gave us a leg up on vocabulary, I think.