Unfortunately I didn't change it until recently due to being unfamiliar and intimidated by html. Got it figured out with a lot of trial and error though.

Haha, pretty close! Just add constant chain smoking to make it hoarse and scratchy, and somehow unexpectedly deep.

It's difficult to describe, as I'm not a linguistics expert, but from what I have looked at, it's going to depend on the dialect of Hebrew used.
Mordernized Hebrew, it's יהוה, which is yodh/yud, he/hey, waw/vav and he/hey.
In ancient Hebrew, ו waw/vav makes an "w" "o", "u" sound, where as in modern Hebrew it's more a "v" sound. That's taking into account that modern Hebrew has the influences of other languages such as Greek, Aramaic, Latin, and of course Yiddish.

That being said, based on the actual Hebrew characters, ו is not silent and makes a "W/o/u" sound in the context of ancient Hebrew. That "w/o/u" sound is definitely influenced by the following ה "he/hey", so it would be "weh", "oeh", "ueh". י yodh/yuh makes a "y" or "ee" sound, So it could be "Yeehweh", "Yeeoeh", or "Yeeueh".
I think it comes down to it being simplified as "Yahweh" for dialect and simplicity's sake, without having to understand the complexities of an ancient language that is largely influenced by how words can be used as both verbs and nouns depending on the context.

edit: I would also like to clarify that I'm not an expert on Hebrew, but working on this comic has helped me in learning more and more about it. I hope to improve that understanding more. :D

It certainly can be confusing! It makes me wish we had a more in-depth understanding of how the language has changed or had someone from that period of time to compare modern Hebrew to.

Hebrew has so many loan words from the surrounding ancient groups, some others Semitic, some not, and you also can observe the differences in the names of their gods, like you mentioned.
It does get difficult and confusing when ancient and unfortunately extinct Eastern and Southern Semitic languages get involved.
I don't think it's a stretch to say that dialect is definitely involved and/or influenced by these surrounding groups, and may have influenced subtle phonetic changes in the Hebrew language depending on the period of time.

I know that in practice, the ancient Hebrews would corrupt the names of gods from surrounding groups/enemies as an insult (Ishtar/Astarte to Astaroth/Ashtaroth, for example), so I could also see YHWH unintentionally being changed as well.
Theoretically this could also be part of the reason why YHWH has so many other names and an unclear proper pronunciation when things went from oral tradition to text, so as to not corrupt and taint the actual name (in addition to the obvious practice of it being disrespectful to actually say YHWH). :O

I'm not entirely sure, but seeing how it has both helped preserve the name and kept it a mystery, one could propose so many different ideas on just the name, and in doing so, keep the tradition and practice alive. Pretty ingenious!