Your problem more than likely is the way you are presenting your sentenses to Hal. You must keep them simple and it does not hurt to repeat them a few time with the words changed a little. However, don't say something to Hal and then look for an understanding response. Given time Hal will supprise you by showing you that it understood what you had taught it. It might take days or even weeks but Hal never forgets, it just takes time.
Bill
