Imitation or Initiation of Language

I was talking with Dylan’s Intervener this week about the Communication Matrix and how initiation is such a key aspect of expressive communication. We’ve found it to be so easy to get in the trap of counting all of Dylan’s signed words as “language”—level 7 on the Matrix—but when we step back we find these signs are often imitations, even delayed imitations of something we had signed quite a bit earlier. Using the matrix helps us recognize when Dylan has moved from imitation to initiation with any of his forms of communication, although this post will primarily focus on the imitation or initiation of formal signs or words.
Now I’m not saying imitation is bad, it is an important, essential step in language development, and when Dylan finally got to the point where he was imitating anything and everything around him we (his school team) were ecstatic.
You see, for many years Dylan initiated topics by his actions, such as looking at light through a Dasani water bottle. To share in this topic with him, we would get a water bottle and move it and look through it the same way Dylan did. As time went on, we could make a change and he would follow us. But this new “monkey see, monkey do” stage of imitation was exciting because it showed the shift in his attention to what we were doing. My attention would be directed elsewhere, then I would notice Dylan looking at me and sitting in my exact position, including attempting to match my facial expression, and even my signs. As I moved, he moved. His gaze and imitation of me, invited me to “talk” with him through imitation games and copying fingerspelling and signs (American Sign Language.) The shared attention and reciprocity was, and is, fun and gives us the ability to share in “conversation” and relationship about topics that are present in the here and now.
Now Dylan can sign many words that he’s learned through imitation. The trick is in the evaluation of his expressive language as he uses those signs. Is he answering a question, such as “more” or “finished” or modeling my signing of those words? Is he imitating my signing of a word, such as planetarium, without understanding w