Proof that Elijah's comprehension is very good:
Elijah was "reading" a book, looking at the pictures and gently turning pages. We noticed he had the book upside down, and told him. Immediately, he turned the book the right way and continued "reading".
Elijah had tipped out all of the pegs out of the peg basket. I asked him to help me pick them up and put them back in the basket. He obliged, so together, we cleaned up the peg mess.
Daddy was on the computer in the kitchen. Elijah wanted to give something to Daddy, and was trying to get to him where there were cables. Daddy told Elijah he couldn't get through that way and to go around the other side. Elijah then walked around the other side of the table.
These examples are on top of the more commonly occurring phrases such as "Go and find Mummy", "Give Daddy a cuddle" and "Give it to Mummy", which are (mostly) followed and most definitely understood.