My 3 yrs old son doesn't chew food, eats all mashed. He has no speech problems, and speaks very well.
He does not chew the food but swallows them. He often runs here and there and does not sit stable at a time. For this I have to put him on the high chair and tie him. I also, put Barney which he loves too much so that he accepts to eat after a big fight to put on chair. He is thin and a slow weight gainer. He also has short attention span and spends few min on one thing and then moves to another. He is very active but very smart. I make sure that I feed him healthy food only with very low sugar intake and no choclate or any junk food. Since many relate non chewing to speech problems, this is not the case of my son at all.
Three-year-old children are busy, inquisitive, and "picky". That's just the stage of their development. They get into things in order to learn, and parents must assure that they do that in a safe environment.
At this age, children may have to attention span to sit through a meal, because whatever else is going on around them is more interesting than sitting at the dinner table. Schedule your son's meals: breakfast, lunch, dinner, and nutritious snacks in between, including a bed-time snack. Do not turn a meal into a power battle, it is not worth it! Meals are supposed to be an enjoyable time spent with the family. If you force your child to eat, he will refuse, because at his age that's one of very few things that he has control over. Instead, prepare a meal, expect that he eats it, and if he does not, let him leave the table. Follow with a nutritious snack in a couple of hours, and when the next meal time arrives, your child will be hungrier!
At 3 years of age, children do not gain weight as rapidly as they did when they were babies. As long as your son's regular health care provider has no concerns, you should not worry about it.