Breaking the Binary: A Systematic Review of Gender-Ambiguous Voices in Human-Computer Interaction

Paper in proceeding, 2025

Voice interfaces come in many forms in Human-Computer Interaction (HCI), such as voice assistants and robots. These are often gendered, i.e. they sound masculine or feminine. Recently, there has been a surge in creating gender-ambiguous voices, aiming to make voice interfaces more inclusive and less prone to stereotyping. In this paper, we present the first systematic review of research on gender-ambiguous voices in HCI literature, with an in-depth analysis of 36 articles. We report on the definition and availability of gender-ambiguous voices, creation methods, user perception and evaluation techniques. We conclude with several concrete action points: clarifying key terminology and definitions for terms such as gender-ambiguous, gender-neutral, and non-binary; conducting an initial acoustic analysis of gender-ambiguous voices; taking initial steps toward standardising evaluation metrics for these voices; establishing an open-source repository of gender-ambiguous voices; and developing a framework for their creation and use. These recommendations provide important insights for fostering the development and adoption of inclusive voice technologies.