CALLS: Japanese Empathetic Dialogue Speech Corpus of Complaint Handling and Attentive Listening in Customer Center

TL;DR

This paper introduces CALLS, a Japanese speech corpus for empathetic dialogue in customer service calls, expanding the domain of empathetic speech synthesis beyond educational contexts.

Contribution

The creation of a new Japanese empathetic dialogue speech corpus for customer center calls and analysis of domain differences in speech synthesis.

Findings

Mixing CALLS and STUDIES corpora biases speech quality improvements.

Domain differences affect expressiveness in empathetic speech synthesis.

Corpus construction methodology for empathetic dialogue in customer service.

Abstract

We present CALLS, a Japanese speech corpus that considers phone calls in a customer center as a new domain of empathetic spoken dialogue. The existing STUDIES corpus covers only empathetic dialogue between a teacher and student in a school. To extend the application range of empathetic dialogue speech synthesis (EDSS), we designed our corpus to include the same female speaker as the STUDIES teacher, acting as an operator in simulated phone calls. We describe a corpus construction methodology and analyze the recorded speech. We also conduct EDSS experiments using the CALLS and STUDIES corpora to investigate the effect of domain differences. The results show that mixing the two corpora during training causes biased improvements in the quality of synthetic speech due to the different degrees of expressiveness. Our project page of the corpus is http://sython.org/Corpus/STUDIES-2.