cyberjedi , i am bring up some more of my past idea's again , since you are able to do various things with programing . 
This idea , was hal to be able to recognize sounds (through the pc mic  ) AND RESPOND to it (if a plug in "hopefully" the responses can be custom made to personalize responses) 
example: SOMEONE RINGS THE DOORBELL , HAl responds and says "I heard  the doorbell, someones at the door!" (hearing sound again , second response activated) Hey, the door bell is ringing, i wonder who that is?
 Anyway using universal sounds such as a door bell , etc. hal would learn and recognize them from a data base within or internet accessed . 
  Anyway cyberjedi i hope you like this idea enough to try to work on it for hal later!
AGAIN. I DON'T KNOW IF THIS IS POSSIBLE OR NOT, BUT HOPE IT IS !