Intertranscriber reliability of prosodic labeling on telephone conversation using toBI

Abstract

Two transcribers have labeled prosodic events independently on a subset of Switchboard corpus using adapted ToBI (TOnes and Break Indices) system. Transcriptions of two types of pitch accents (H* and L*), phrasal accents (Hand L-) and boundary tones (H% and L%) encoded independently by two transcribers are compared for intertranscriber reliability. Two commonly used methods of reliability measurement, ‘transcriber-pair-word’ comparison and kappa statistic, are used for comparison with previous reports on the intertranscriber consistency. The results obtained from transcriber-pair-word comparison are: The overall agreement on the presence or absence and choice of pitch accent is 86.57%. The agreement on the presence or absence and the choice of phrasal accent is 85.63%. The presence and choice of boundary tone is 89.33%. When both transcribers agreed that there is at least a phrasal tone, the agreement on the choice of the type of either phrasal accent or boundary tone is 73.86%. The kappa coefficient of agreement (K) of 0.7 to 1 indicates the degree of reliability to be from good to perfect. A kappa coefficient of 0.75 is obtained for agreement on the presence or absence of pitch accents, 0.67 for the presence of phrasal accents, and 0.61 for the strength of disjuncture between phrasal accent and boundary tone. Comparison of the present results with those of previous reliability studies [1][2][3][4] suggests that some higher agreement rates for this study may result from our adoption of fewer labeling distinctions in the transcription of pitch accent events. The results for phrase boundary labeling suggest that spontaneous speech of the type found in the Switchboard corpus is harder to code for the degree of disjuncture between prosodic domains than is read speech.