The text located in the U.S.S.R., namely, the Codex Leningrad B 19 A , used for BibliaHebraicaStuttgartensia (BHS), vowel-points the Tetragrammaton to read Yehwah´,Yehwih´ and a number of times Yeho·wah´, as in Ge 3:14. The edition of the Hebrew text by Ginsburg (Gins.) vowel-points YHWH to read Yeho·wah´. While many translators favor the pronunciation "Yahweh," the NewWorldTranslation continues to use the form "Jehovah" because of people’s familiarity with it for centuries. Moreover, it preserves, equally with other forms, the four letters of the divine name, YHWH or JHVH.—See ad under "Jehovah."
After reading this post, I typed in YHWH in the WT cd rom. This is from the Rbi8 which I think is the Reasoning book but not sure. This point in bold caught my eye when they say "While many translators favor the pronunciation "Yahweh," the NewWorldTranslation continues to use the form "Jehovah" because of people’s familiarity with it for centuries. Moreover, it preserves, equally with other forms, the four letters of the divine name, YHWH or JHVH.—"
Are they basically saying that they pronounce Jehovah as that because it is common, accepted and has familiarity? Hmmm. I'd stick to plain ol YHWH then as there is not as much controversy to that name.
Just my two cents.