the point is the no one really knows how to pronounce YHVH, in fact we are not even sure it is a word, it may be an abbreviation or a contraction of several words or just literary symbols. it has been transliterated as both "Jehovah" and "Yahweh" both are just guesses and one is not more correct than the other.
i am quite sure that if you direct your prayer to the Living Creator of all that is was and ever shall be that he/she/it will hear you, no matter what name you use. God looks on the heart, and does not sit with arms folded until the magic word is used. God reacts to faith love and humility, call God Fred if you want i don't think God will mind.