“Yahwah” is the way they have decided to transliterate יהוה, the four-letter Hebrew name of God known as the Tetragrammaton. It is pronounced YAḤ-wah; the “Ḥ” is a voiceless pharyngeal fricative, which means it is slightly raspy. In Judaism, the name of God is considered too holy to be uttered. The Hebrews believe that they can, and indeed should, use God’s name so that there is no confusion about whom they worship. “Yah” is a shortened form of Yahwah. (NB: The Tetragrammaton is usually transliterated as “Yahweh” and pronounced YAH-way.)