One Voice Fits All?

ing with credit is permitted. To copy otherwise, or republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee. Request permissions from permissions@acm.org. © 2019 Copyright held by the owner/author(s). Publication rights licensed to ACM. 2573-0142/2019/11-ART223 $15.00 https://doi.org/10.1145/3359325 Proc. ACM Hum.-Comput. Interact., Vol. 3, No. CSCW, Article 223. Publication date: November 2019. 223:2 Julia Cambre and Chinmay Kulkarni has also advanced considerably in recent years; new models based on deep neural networks such as WaveNet are now capable of generating increasingly varied and more human-sounding speech compared to prior approaches like concatenative or parametric synthesis [30, 63]. This explosion in the popularity and pervasiveness of voice interfaces—along with rapid improvements in speech technology—adds new urgency and complexity to the question Nass and Brave raised nearly 15 years ago. Within the Human-Computer Interaction and Computer-Supported Cooperative Work community, this trend has not gone unnoticed. In recent years, researchers have studied voice assistants from a number of angles. Several papers have explored users’ patterns of everyday use with common voice assistants like Alexa, Siri, and the Google Assistant [3, 44, 66, 70]. Others have considered usability challenges faced by natural language processing errors [58, 74], and future use scenarios such as leveraging speech to navigate videos [13] or promote workplace reflection [36]. There have also been efforts to establish a more theoretical or vision-setting perspective on voice technology: for example, Cohen et al. [18] and Shneiderman [72] have weighed in on the merits of voice as an interaction medium, while Murad et al. [56] proposed an initial set of design guidelines for voice interfaces. Within the CSCW community specifically, voice interactions have also received considerable attention in recent years, with papers and workshops on topics ranging from accessibility [12], to automated meeting support [49], Wizard of Oz prototyping techniques [45], privacy [37], multi-user interaction [67], and more. While these papers all offer useful perspectives on voice interface design, their focus has almost exclusively been on what voice assistants say in conversation, rather than on how they say it. This paper poses a seemingly straightforward question: What should the voices of our smart devices sound like? Specifically, as we move towards a future in which users interact through speech with not just smartphones and smart speakers, but with an increasing array of everyday objects, selecting a voice identity for these smart devices remains an open design challenge with important social consequences. This paper introduces a research framework for understanding the social implications of design decisions in voice design. To demonstrate the utility of this framework, we both summarize existing research using it, and discuss a sampling of new research questions it generates. To generate this framework, we consider the design space of smart device voices, and organize the literature around what we know about how the features of a synthesized voice shape our interactions with speech-enabled technology. In doing so, we rely heavily on research in human-robot interaction (HRI), while still incorporating research from other fields such as social psychology and design research. We are not the first to propose a framework for voice design. For example, Clark et al [16] mapped out the existing space of research on voice in HCI through a recent review of 68 papers. Through this review, the authors suggest a set of open challenges for the field, including a need for further design work and studies of multi-user interaction contexts. Importantly, however, their review deliberately excluded papers focusing on embodied interfaces. Our framework complements Clark et al.’s review by focusing explicitly on this area of embodied voice design. Our HRI-based perspective also distinguishes this paper from recent work that studies the design of speech interfaces with voice in isolation. For example, Sutton et al. propose a framework based on findings from socio-phonetics [71]. While studying voices in isolation prevents the confounding effects of voice with the effects of embodiment, in practice embodiment, form-factor, and contexts of use do indeed influence how people perceive voice interfaces and social robots [23, 28, 34, 50]. In our work, we hold that these attributes are not undesirable confounds, but necessary dimensions of analysis: smart devices necessarily will possess form, contexts of use, and perhaps even human-like embodiment. Thus, because embodiment and form and voice together affect perception is precisely Proc. ACM Hum.-Comput. Interact., Vol. 3, No. CSCW, Article 223. Publication date: November 2019. One Voice Fits All? Social Implications and Research Challenges of Designing Voices for Smart