When Helen and Annie return from the guarded house why did Helen test Annie and her parents at the table from the story the miracle worker?

Helen tested Annie and her parents at the table to see if they truly understood and were committed to using the new method of communication she had learned. By knocking over the pitcher of water, she was challenging them to apply the language breakthroughs that were established during their time at the guarded house and to continue pushing her to learn and communicate effectively.