Since Thursday of last week it has become apparent that Bugs is doing more than just babble babyishly (babyishly is a real word - trust me). It is now quite clear that he is saying "Dad" and "Dada" when he sees me. The clincher for us is that he no longer says "Dada" when he sees his Mummy, only when he sees me. He's pretty clear and forceful about it, too (especially when he first sees me when I come home from work).
I'm the first word.
Edited 7/2 for a typo