31. The system of claim 24 wherein the one or more software routines also cause the computing system to generate a challenge scenario comprised of said candidate challenge sentence and one or more visual and/or text cues, which challenge scenario is stored in said database.
31. The system of claim 24 wherein the one or more software routines also cause the computing system to generate a challenge scenario comprised of said candidate challenge sentence and one or more visual and/or text cues, which challenge scenario is stored in said database. 34. The system of claim 31 wherein the one or more software routines also cause the computing system to annotate said candidate challenge sentence with first content elements for said visual and/or text cues found in said at least one first utterance and with second content elements for said visual and/or text cues found in said least one second utterance.