In Hebrew it is יהוה or yod ha vav he. The pronunciationis according to the grammar rules of Hebrew. Yahweh is taken from the Hebrew verb Haya, or to be. Yahweh is the Hebrew eqivalent to the gerund in English(and other languages.). When we convert the verb into a gerund in English it is simply taking the infinitive, dropping the "to" and adding "ing" to the stem. and example, to read, reading. It becomes a noun. Everyone knows how to pronounce it. It is the same in Hebrew. Now why do you suppose everyone has settled on Yahweh or with another accent Yahveh? It is because the noun form of a verb is just as easy to pronounce as it is in any other language.
Why you bring up the J sound again, I do not know. There is no J sound in the Hebrew alephbet, nor in the spoken languge.
The mistaken error in translating by non-Hebrws to Jehovah, is just that, an error. Like when it was translated for centuries that Moses ha horns emitting from his ehad when he came down from the mount.
It is not so terribly important to pronounce any proper noun absolutely correctly in most languages. Merriam Webster teaches there is NO correct pronunciation of a proper noun in English, only primary, secondary, tertiary, etc. pronuciations. We do always attemtp to use the primary in any proper use of any language, but the accent is not the final dectate on wheterh a noun is correctly pronounced or simply pronoundec using another acepted pronuctiation. To expect one prnuciation because it does not suit one is pedant and ignorant at best.
