I’m finding this whole discussion rather intriguing, but I have to interject a point that might make all previous and preceding arguments useless.
It’s obvious we’re dealing with very old words here – words from languages that are essentially dead (Aramaic) or have changed considerably over the past couple of millennia (Hebrew, and don’t deny it – Classic and Modern Hebrew are different). We’re forgetting our transformational linguistics here, people!! At this far-removed date, we can only guess at what the “true” source of abracadabra really is. Our pronunciations are different than the originals, and the words will have been mangled by their passage from person to person, age to age, with no commonly written form to keep the structure pure. Remember that most people, even the illusionists of the time, were illiterate. Sloppy speech habits and contact with other languages have smudged this page permanently.
That said, please continue with this discussion as you like. It’s great, it’s fun, and it brings me back to my days of studying linguistics. It was only my minor, though, so I could be less than right. Either way, Keep On Dopin’ !!