Our methodology was to pretend not to understand Jennie's requests unless they were signed. She didn't know the sign for play, but she slapped the floor. It was a deliberate movement that to me looked uncannily like a sign. As an experiment, I slapped the floor. She slapped it and rattled the doorknob. I signed, Jennie want to go outside and play? But I used her sign for play, slapping the floor. She slapped the floor three or four times in succession, signing in between Yes, yes, yes. So I rewarded her with a play session down by the brook.