As far as i know, UMG Widget are based on “Slate” a programming language made up by some of the Epic Games guys. They invented UMG to get rid of the C++ horror with Slate, because it’s not that easy to learn, at least not for me.
Rama made some Tutorials for Slate:
But i would recommend to stay with UMG since they made it for us, so we don’t have to use Slate.