Q
My sister's boy is now two years and four months old and has yet to peep one single word. When he tries, all that comes out is a googeley sound. She refuses to take him in to get checked, as she is afraid to hear something is wrong with him. He's very smart and seems to be able to hear you when you speak to him. Is this normal or could he have a birth defect?
A
Assuming your nephew is a healthy pre-schooler, has not had any significant past medical history, and is otherwise developmentally normal, I feel there is cause for concern. I agree with you that he should be saying more words by this age. In fact, we would expect him to already have a better than 50-word vocabulary and be able to put two words together. A normal child's speech also has progressively improved clarity--roughly half intelligible by two years of age, moving toward fully intelligible by four years.
It would be very worthwhile having your sister speak with his physician, so an appropriate referral for evaluation can be made. Your nephew may just have some difficulty in producing or expressing speech. Although this type of problem can occasionally be traced to a specific underlying factor, it is much less common to identify a "birth defect." I am glad that you think he hears well and is able to follow directions, but I generally would still confirm normal hearing. Help your sister to understand that the earlier something can be identified and treated, the less likelihood for any life-long problem and the brighter the future should be for your nephew.