I believe it stems from the fact that the name YHWH, in the Hebrew, had no consonants, and sounds like a breath when it is spoken. It’s like the Holy Spirit is known sometimes as a ‘rushing wind’, and if you say the name Yahweh slowly, with a deep breath, it does sound like breathing! It’s said that every baby says the name of Yahweh with its first breath! The first part, or the Yah, is the intake of breath, the last part of the name, Weh or just Wh, is the exhaling of breath. I think this is a beautiful concept!!