I am in a similar situation. A family just started with me. A three year old boy and a five year old girl. I can't understand the boy when he talks. He points and grunts. He tries to speak but it's unintelligible. The girl also has speech issues. I was trained by a speech/language pathologist in an elementary school to help kids with speech. Because I'm licensed in Manitoba I can suggest a referral to see a speech pathologist. My coordinator came out to observe the boy and she confirmed my concerns. I spoke to the parents about this they were very angry and said their kids had no problem. It turned ugly fast to make a long story short. I'd like to terminate but I can see this family will bad mouth me as they are that type of people. I know I shouldn't worry because I have a very good reputation in the community and other parents are very happy with having their kids here.
So I guess if this is the first time you've dealt with this I'm sure the community will ignore whatever this family may say about your daycare. Good luck.