Mapping the Dialog Act Annotations of the LEGO Corpus into the Communicative Functions of ISO 24617-2
Table 3: ISO 24617-2 communicative function distribution in the LEGO corpus.
['[BOLD] Dimension', '[BOLD] Function', '[BOLD] System  [BOLD] Count', '[BOLD] System  [BOLD] %', '[BOLD] User  [BOLD] Count', '[BOLD] User  [BOLD] %', '[BOLD] All  [BOLD] Count', '[BOLD] All  [BOLD] %']
We can see that communicative functions in the Task dimension are more predominant for user segments than for system segments, with 92.87% of the user segments having communicative functions in that dimension versus the 78.15% for system segments. While for system segments the most frequent functions are Check Question (24.84%), Set Question (21.88%), and Instruct (19.95%), for user segments those are replaced by the Answer (28.70%), Confirm (22.81%), and Disconfirm (21.69%) functions. This is coherent with the nature of the dialogs, which typically consists of the system questioning the user to obtain the required information. All segments considered, 83.44% have communicative functions in the Task dimension. Since there are more system segments, the most frequent functions are the same as when considering those segments only, but with lower impact – 15.92%, 15.50%, and 13.53%, respectively.