S.G.
You said he sometimes "signs" the word "more". Have you been teaching him sign language? I read that it's very good to do, but that sometimes children who learn signing learn talking a bit later because they don't NEED to. They can communicate and get their point across, so they don't need the actual spoken words, so they don't learn those as soon.
Apart from that, my nephew was 2 and a half and still couldn't say a single word. Now he's a motor mouth. He DOES go to speech therapy twice a week to work on pronunciation. And before he was doing that, the doctor said that it helps to phrase things differently. Like instead of saying "where is the clock?" and letting him point, they should rephrase that and point to the clock and say "what is that?" because then HE has to do the speaking. If you are reading a book with him, you can leave a word out and let him fill it in. Like "And then the dog grabbed the ....." and you point to the ball and let him say "ball". If he needs help, make the sound of the first letter. So "dog grabbed the.....b" so he has to finish it.
Hope that helps!!