Complex sentence: Jehovah's Witnesses emphasize use of God's biblical name, represented in the original texts by the Tetragrammaton, and in English they prefer to use the name, "Jehovah".
Split into simpler sentences: Jehovah's Witnesses emphasize use of what they consider to be God's biblical name, represented in the original texts by the Tetragrammaton. In English they prefer to use the name "Jehovah".