[knarf]

Yes, you're correct, and it is MY belief 99% of Americans, when they SEE that word, subconsciously says EYE SAY AH ... or stumbles because they are not bible/church people (who are VERY familiar with the printed word AND the pronunciation of; EYE SAY AH.

The added "S" on the word occurs once (that I can remember" in the KJV NT ,,, but I can't remember where, nor will my search engine take ne there

[Trot]

The NT spelling is Esaias, found in 21 vv, beginning in Mt 3.3.

[trebb]

When I want to do searches, I use Biblegateway.com - just ran “Isaias” through about a half dozen versions and came up empty.