1.   Currently available speech recognition systems impose a selection of constraints on the input to simplify the speech recognition task.

2.   The morphology of the system was simplified in a manner suited to the recognition task.

3.   This makes it clear that the subjects found the recognition task difficult.

4.   This is evidence that subjects who knew the route well performed no differently in the recognition task from those subjects who knew the route less well.

5.   This might make the recognition task too easy for subjects.