When playing choose 2 / 3 simple words or sounds to model. Try to create predictable sequences and then stop / pause and see if child reacts or responds. Eg. May get into sequence of pushing car up a ramp and let go saying “up, up, up, down” after modelling this a few times you may “up up up…..” and wait. Again if they don’t respond after a few seconds fill the gap but wait long enough for them to have opportunity to fill gap.