It seems like in the past couple of weeks, a switch has flipped in Alex’s head, and suddenly he’s a human being. He just made a huge leap in sort of understanding.

Anyway, without further ado, I present to you videographic evidence:

Alex saying “mama”:

 

Alex doing “bye bye”:

 

Alex doing “so big”:

 

Alex signing “more”:

 

Other signs that he knows include “milk” and “all done”, and he understands “book” and “train”, but doesn’t do them himself.