Hi my son is 3 year old his weight is 11.5 and his words are not so clear .can u help me with dis two issues

Take high fiber low fat diet. Drink lot of water everyday. Take small and frequent meals at regular intervals of 2-3 hrs. Avoid outside food completely. Do crunches and pushups daily to reduce belly fat. Ask me directly for customized diet plan for you. 

The ideal weight for a 3 month old baby should be between 5-6kgs.

if your son has started speaking monosyllables, it is an okay start. you need not worry. any other learning disability that you know off?