I have a 2-and-a-half-year-old son who seems to respond to his name only when he likes to. When someone waves "goodbye" to him, he just stares at the person until the person's long gone, and then he'll say "bye." What suprises me is he doesn't repeat to what we say, but he sings along with almost every song on TV or radio. I feel I can't communicate with him, and as a result, I can't potty train him. Should I be concerned? Will he start talking at some point?
Songs he sings that are heard on the radio or TV remain the same every single time, so he sings as a result of memorization. The songs are consistent and predictable, but spontaneous language is not. When your son wants to eat or wants a toy, how does he let you know? Does he point? Does he grunt? In order to communicate with your son, continue to use language, point to objects and name them, and encourage him to repeat a word or phrase after you. If he gestures that he wants milk, ask, "Do you want milk? Say, ‘Milk, please.’" When he uses these words, give him milk right away. Continue to work on this repetition (e.g. "This is a ball. Can you say ball?").
When toilet training him, you don't need him to do a ton of talking. Explain what you are doing, put him in Pull-Ups or underwear, and take him to the bathroom every 30 minutes. When he has success going potty, offer him a small reward such as an M&M or cut-up pieces of a gummy worm. Do not punish him if he has an accident. Instead, remain neutral and say, "You can try again next time."
It’s possible your son's lack of response may stem from difficulty hearing certain levels of sound and his delayed response may be a result of slowed processing. Consult your pediatrician and request a hearing test and a central auditory processing evaluation. Another source of information and support is Early Intervention. Ask for a developmental evaluation to determine if your son is behind in any of his areas of development, such as speech. This may qualify him for in-home services.