Sounds like you have a little smarty-pants on your hands!! DD1 is 3 in August and she's talking about the same as you describe - everyone says she's a great talker and strangers are surprised when I say she's not 3 yet, but then she's always been a bit ahead on her milestones so DH and I are used to it and see it as normal. 'Normal' is such a huge scope, I think it's great that your little dude has such great comprehension and grasp of language at this age, it certainly makes my life easier being able to understand DD1 rather than her and I yelling nonsense at each other because she can't say what she wants and cracks it!