Jahan's aptitude for sentence structure improves with each day that passes. I doubt he actually understands the grammatical significance of using "is" or "the" but he often seems to know when to use them correctly. Recent examples of questions and statements:
"What's down there?"
"Where's Jahan's hat?"
"Wake up, George! It's morning!". The last comment resulted from Jahan being woken with the words "Good morning, Jahan. Is George still asleep?".
(George is Jahan's giraffe).