32. A method as in claim 1 , wherein the step of grouping valid phrases into classes of equivalent valid phrases further comprises the step of identifying equivalent valid phrases as valid phrases having contexts that overlap by greater than a predetermined degree.
32. A method as in claim 1 , wherein the step of grouping valid phrases into classes of equivalent valid phrases further comprises the step of identifying equivalent valid phrases as valid phrases having contexts that overlap by greater than a predetermined degree. 33. A method as in claim 32 , wherein the step of grouping valid phrases into classes of equivalent valid phrases is performed using one or more agglomerative clustering methods.