Open Question: Speech delay in 2 year old, what else can we do?

My son, he used a word, is considered a serious delay. We are in the child development classes and speech therapy, but he did not seem to work. Him to the ear, nose and ears to ensure his good, they say they are there, but the scheduled sleep study ruled out as a cause of sleep apnea him. Is there anything I can help him? I think I've tried everything, but it seems there is no work. He knew that at least 10 signs, so we can actually communicate, but there is a practical reason, children and language delay? Like can not be missing anything from our throat or nose in the (ENT only check the ears?) Which is led him to delay or just happen?