Welcome to you, Lukaszd. I see in your bio that you are about to be "beatha" (born) into the 'real world' when your
life as a student ends. Good luck, Dear!

Now--here is my very imaginative genealogy:
I began by imagining how uisge might be pronounced,
and came up with, roughly, oos-ga. From there, I got to
juice->liquid->water->vada->vodka. (?)
Beatha looks like breathe, which is what you do when you are born, and live. Beatha->vita?