Lea, it would depend on what the problem is, if it's a problem with how he uses his tongue, then I would say no it wouldn't effect his cognitive (thinking) processes, but if it were a hearing problem, then possibly it would cause he can't hear to learn things, then it could be a problem with how he processes language, so it would be his thinking processes that is the problem, affecting his language....there are so many things it could be!

Have you had his ears checked lately? Maybe he has a problem hearing?

And that info I gave is just a guide, there is always going to be children at both ends of the scale, maybe Nixon is just at one end of the scale. Don't get too worried about it, he's only a baby still, and if he does have a problem you have caught it early which is great! Don't stress! Just get he assessment done and go from there.