How can I get my son potty trained?

My son is almost 3. He has a speech delay and isn't talking very much. We're lucky if we get 1-2 words from him a day. Otherwise it's just babble. He stays dry all night and during naps. He refuses to keep his clothes on and I'm constantly having to clean up pee. He is slowly destroying our carpet and we are renting. I put him on the potty every 30 min. He just holds it till he's in the living room again. What can I do???