This document, dated June 29, 2008, decries the fact that despite instructions to the contrary, “in recent years the practice has crept in of pronouncing the God of Israel’s proper name, known as the holy or divine tetragrammaton, written with four consonants of the Hebrew alphabet in the form יהוה, YHWH.”
... Moreover, in Catholic religious services, hymns, and prayers, God’s name “YHWH is neither to be used or pronounced.”