I've made threads before comparing 'Middle Welsh' to Old Hebrew (which disappeared in 200AD); remarking that they're identical spoken. This has been known since at least 1675, in a book wrote by Hanes y Fydd (Charles Edwards), with a number of Cmabro-Brittanic-Hebraism parallels.

For example

1.English
2. Welsh
3.Hebrew

1. And they shall fill your house and the houses of all your servants.
2. Amelhau bytheu chwi a bythau holl ufyddau chwi
3. Umalu bathe choh and bathei col avedo choh


I took this to mean that the Assyrian Scattering of the Northern Kingdom of Israel (~723BC), may have given rise to Hebrew migrations one of which being settling in Wales; but I do NOT think this is the case and I'll explain why.

I am no Chomsky (his real expertise is linguistics) but I've noticed that 'Old Hebrew' (which is nothing like new Hebrew) is a really "weak" language. What I mean by that, is Old Hebrew compared to say Latin, or English, is like VB to C++, and even that is giving it too much credit.

There are around 500 words in Old Hebrew, if you can even call it a language (primitive African languages are more advanced); it's a mongrel of Aramaic, Arcadian and Assyro-Babylon and Canaanite.

It was the "Yiddish" of the ancient world, or the Modern New York Jewish vernacular (I met a NY jew, funny guy one for another day). Old Hebrew was NOT so much a real language, but more the way they probably spoke, to probably avoid others understanding what precisely they meant.

Now to my original point, I think the second destruction of the Temple in 70AD led to migrations of Jews to Wales, where they lived on the periphery in the borders as bandits, like they did in the ancient world.

This is why Middle Welsh and Old Hebrew share similarities.