Voice banking to support individuals who use speech-generating devices: development and evaluation of Singaporean-accented English synthetic voices and a Singapore Colloquial English recording inventory

Abstract

Voice banking involves recording an inventory of sentences produced via natural speech. The recordings are used to create a synthetic text-to-speech voice that can be installed on speech-generating devices. This study highlights a minimally researched, clinically relevant issue surrounding the development and evaluation of Singaporean-accented English synthetic voices that were created using readily available voice banking software and hardware. Processes used to create seven unique synthetic voices that produce Singaporean-accented English, and the development of a custom Singaporean Colloquial English (SCE) recording inventory, are reviewed. The perspectives of adults who spoke SCE and banked their voices for this project are summarized and were generally positive. Finally, 100 adults familiar with SCE participated in an experiment that evaluated the intelligibility and naturalness of the Singaporean-accented synthetic voices, as well as the effect of the SCE custom inventory on listener preferences. The addition of the custom SCE inventory did not affect intelligibility or naturalness of the synthetic speech, and listeners tended to prefer the voice created with the SCE inventory when the stimulus was an SCE passage. The procedures used in this project may be helpful for interventionists who wish to create synthetic voices with accents that are not commercially available.

Keywords:

• Intelligibility
• naturalness
• preference
• Singapore
• Singaporean Colloquial English
• speech-generating device
• synthetic speech
• voice banking
• voice donor

Acknowledgments

The authors wish to express sincere gratitude to the participants of this study.

Disclosure statement

H. Timothy Bunnell directs the Nemours Speech Research Laboratory that developed the ModelTalker software and voice banking service. Jason Lilley is an Assistant Research Scientist at Nemours Speech Research Laboratory. Nemours is a nonprofit health care system, and the Speech Research Laboratory provides voice banking to clients on a fixed fee-for-service basis. We have no known conflict of interest to disclose.

Notes

1 Sennheiser USB headset microphone © is a product of Sennheiser electronic GmbH & Co. KG, Germany.

2 HP laptop EliteBook 830 G5© is a product of the Hewlett-Packard company, Palo Alto, California, United States.

3 What’s App, Instagram, and Facebook are owned by Meta Platforms Inc., Menlo Park, CA

4 Siri © is a virtual assistant that is part of Apple Inc.'s iOS, iPadOS, watchOS, macOS, tvOS, and audioOS operating systems.

Additional information

Funding

This study was funded by Singapore Ministry of Education (MOE) under the Education Research Funding Programme (SUG 06/18 CM) and administered by National Institute of Education (NIE), Nanyang Technological University, Singapore. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the Singapore MOE and NIE.