Would People Mumble Rap to Alexa?

Casey C. Bennett, Minha Lee

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

1 Citation (Scopus)


Unclear speech, like mumbling, is difficult to understand for people, and even harder for conversational user interfaces (CUI) to process. Yet, there are multiple reasons why unintelligible speech is meaningful between humans, playing a critical role in social dynamics and status signaling that evolved in humans over time allowing us to form cohesive social groups for survival. For example in modern times, humans often use such changed speech in order to make themselves understandable only by in-group members, e.g. "mumble rap", while subtly excluding out-group members. As such, we argue here that future CUIs must be attentive to how people use various forms of non-standard changed speech (e.g. mumbling, dialect, slang, inflection) to express themselves, lest CUIs be socially inept. Based on psychological, linguistic, and cross-cultural research, we point out several major challenges for researchers: 1) current CUIs typically omit non-standard speech like mumbling which are critical to human social communication, and 2) in the future humans may innately form ingroups with their personal CUIs resulting in speech behaviors meant to exclude outgroup members (both humans and machines). Both of those challenges require more research to address. Moreover, the use of changed speech for status signaling and ingroup/outgroup (IG/OG) signaling appears to be a phenomenon that varies across diverse cultures, languages, and situations, which CUI designers and engineers need to be mindful of going forward.

Original languageEnglish
Title of host publicationProceedings of the 5th International Conference on Conversational User Interfaces, CUI 2023
PublisherAssociation for Computing Machinery, Inc
ISBN (Electronic)9798400700149
Publication statusPublished - 19 Jul 2023
Event5th International Conference on Conversational User Interfaces, CUI 2023 - Eindhoven, Netherlands
Duration: 19 Jul 202321 Jul 2023


Conference5th International Conference on Conversational User Interfaces, CUI 2023

Bibliographical note

Publisher Copyright:
© 2023 Owner/Author.


This work draws from research across many different projects, including a grant from the National Research Foundation of Korea (grant# 2021R1G1A1003801). We would also like to thank our various research collaborators from over the years.

FundersFunder number
National Research Foundation of Korea2021R1G1A1003801


    • Artificial agents
    • Ingroup/Outgroup
    • Language
    • Signaling
    • Speech inflection


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