So first, we need to make sure that they understand what a question is. Okay, the nature of a request for information along with a response. Then, we need to clarify the difference between a specific “you” and a collective “you”, because we don’t want to know why Joe Alien is here, we want to know why they all landed. And purpose requires an understanding of intent. We need to find out: do they make conscious choices? Or is their motivation so instinctive that they don’t understand a “why” question at all? And, and biggest of all, we need to have enough vocabulary with them that we understand their answer.