And 'papa' is a synonym of grandfather in eastern Georgia (e.g. Kakheti).
Regarding the first "word" (a nonsense actually) - it is usually "Aghu". Even before a baby starts talking anything, parents encourage them - "Say aghuu, aghuu" :)
Is it just Georgian or the entire Kartvelian language family?
the short answer is i don't know. however the kartvelian group consists of only four languages, geographically near each other, and they are 'closely related[1]' according to wikipedia. one might expect a some degree of mutual intelligibility, as between czech and slovak, for example.