I'm not sure, but at several occasions I got the impression that Luna tries to immitate what I'm saying. When I'm coming home from work, I usually say "Hi, Luna!" and "Na?" (also means something like "hi" or "what's up?" in German) and sometimes she's replying with something that sounds like "nga?", and it almost has the same sound. So I thought she's trying to greet me with my own words.

Kirsten