Anyone who know any Aramaic at all knows that the Aramaic used in the land of Israel is very different than other dialects, such as Babylonian Aramaic.
The Aramaic that appears in Eretz Yisrael sources like the Talmudh Yerushalmi and Midrash Rabbah, sifre and pesiqtah rabathi are very different than that of the zohar.
The Zohar is a babylonian style aramaic with a few changes to word endings like lon instead of leho in babylonian and other minor examples. These superficial changes are obviously meant to disguise the writers lack of fluency in "Palestinian" Aramaic.
I have studied aramaic for many years and I can tell the difference in Aramaic styles between Babyonian and "Palestinian" Aramaic.
This in and of itself is proof this was not written by a jew in the 2nd century.