What?

Both of my children have been early and articulate speakers. Hannah was saying a few recognizable words by the time she was 8 months old. She was making simple sentences by the time she was a year old. At her 18 month checkup, she took one look at the pediatrician and said, pointing: "That' s a stethoscope. You are going to listen to my heart." By the time she turned 2, she could string together a couple of nice long sentences, make up stories, recount past events and dreams. She can--when she feels like it--speak in a very poised manner. Her vocabulary is rather impressive. Recently, she asked me if we could look at some satellite images to make sure no hurricanes are near us.
Jonah didn't start talking quite as early as Hannah did, but he is definitely ahead of most of his peers. It's nice to be able to communicate so well with him. He can tell us what he want. He can ask to be held. He can tell us if something is wrong. Sometimes though I have no idea what he is saying. He'll keep repeating the same gibberish, I'll keep asking him "what?", we both get frustrated.

j: I want some hjyunfgshytg.
N: What?
j: I want some hjyunfgshytg.
N: What do you want?
j: Hjyunfgshytg.
N: What?
j: I want hjyunfgshytg!
N: What? Can you show me?
j: Hjyunfgshytg, I said!!!!