My son was a late talker and a lot of his consonants are pronounced wrong. I talked to his ped at his 3 year check up, and he didn't think it needed attention. We waited months, and had unsuccessful calls to the school system to try with them, when I happened to drive past a speech pathologist's office here in town. I called, had him evaluated next day, and it turns out he's got a pretty strong tongue thrust that causes the majority of his consonants to be formed with his tongue in his teeth. He goes three days a week.
So, talk to the pediatrician about it. But if you're concerned, do a Google for an SLP, and set up an appointment.
Mom to a girl - 6, a boy - 4, and Baby - 2