My child is incredibly smart even "gifted".

At 4 most kids can read a bit, sing songs, recite the alphabet, even do basic math. That part of the brain really has nothing to do with speech, it also doesn't mean that the child is gifted. Reading, singing, that's normal for a 4 year old.

She may have a speech impediment. Have you ever had her tested for speech problems? If not, I would encourage you to do so. The sooner she gets help if she has speech issues, the better off she'll be later on. It can effect her schooling. I'm speaking from experience. My son had speech problems, and at 4 we did get him help. Thankfully the school he went to is great, and he also got help with his speech problems there, once he entered kindergarten.

I am almost "scared" to even say anything, he may well be talking great for a 4 year old, not for a 10 year old. Esp when parents start throwng that gifted word out.

But do you require him to do good sentence when he is asking for things and so on.

What is the converstation level of other members of the household

I really suggest that you ask your pediatrician. It could be something serious. It could be nothing. Your doctor will be able to tell you what is "normal" for a child that age, and can tell you if further investigation or testing is needed. We can speculate on it here, but the only person who can really begin to address your concerns is your pediatrician. I will say that if you do have concerns about speech, you do want to address them before your child begins kindergarten. We all want to give our children the best start possible, and that may be a part of it.