There isn't a lot to report, given that so far he says only three "words". B and I disagree on the definition of words- B is fairly strict, saying that it needs to be the correct usage ("Moo", "'Nana" and Big Bro's first word, a gutteral click to sound like B's phone don't count). I am more open minded on this matter, and accept anything that is repeatedly and somewhat exclusively used in the context of the object/event and has an identifiable connection to the object/event.
With that being said, I would say that Little Bro's first three words were:
1. An abbreviation of Big Bro's name (I'm very pleased about this one!)
2. "Toot-toot"- train (Little Bro is the ultimate diplomat to be naming items at the centre of Big Bro's world first!)
3. "Car-Car"- car
The last one is rather broadly applied to anything vehicular that isn't a toot-toot: real car-cars, solitary carriages or engines of toot-toots, and yesterday, Little Bro pointed to a plane flying over us and very proudly said "car-car".
Just to show that I'm not excessively liberal in my definition of words, I don't yet accept "mamamamamama" as a real word: it is Little Bro's way of saying "excuse me world, I'm really needing some attention", especially used in the middle of the night. I would like to believe that this is not the definition of Mama!