You can teach some interactive play by using play scripts. The child can read his/her “part” and then practice it enough interactively so that it becomes part of play. The more scripts the child learns, the more generative language will come out of it. If the child can’t read, use pictures.

Also included are some sample play scripts. If you want more, here’s a link.

You can also record frequency of spontaneous commenting during play if that is your goal.

Another great way to teach play is with video modelling. You can easily take a video of yourself or a sibling playing with a toy/activity and then use it to teach the learner what to do. Include language within the video models.