Background: Voice output communication aids (VOCAs) are a key form of aided communication within the field of augmentative and alternative communication (AAC). In recent years, rapid developments in technology have resulted in an explosion of devices available commercially, yet little research has been conducted into what people who use VOCAs think about them. Aims: The aim of this research was to explore the perceptions of communication aid design from the perspective of end users and AAC professionals, with the objective being to inform and influence the design of future devices. Methods & Procedures: A two-part study was conducted: interviews were undertaken with people who use VOCAs, and questionnaires were distributed to those who use aided communication and to AAC professionals. Analysis of the interview data was carried out using a qualitative method based on framework analysis, whilst descriptive statistics were generated from the questionnaire data. Interview participants were an opportunity sample of VOCA users within a defined region of the UK. Those recruited were over the age of 12 years and able to engage in the interview process; they were identified through the caseloads of local Speech and Language Therapists specializing in AAC. The questionnaire was marketed to the AAC community throughout the UK. Respondents were self-selecting as those using aided communication, their carers and AAC professionals. Outcomes & Results: Eighteen people participated in the interviews. Questionnaires were completed by 43 people who use aided communication and 68 AAC professionals. The data suggest that current devices are considered to be neither reliable nor durable by users and professionals. Although features given a higher importance ranking are more likely to be perceived as available, a number of important design deficits are identified by users and/or professionals. Simplicity of design (and use) and the desire for devices which support communication that is as fast and spontaneous as possible also emerge as key requirements. Synthesis of the data produced a framework with three main themes covering the range of issues which influence the successful use of a VOCA: specific aspects of the design of a device; the consideration of the wider picture around the person; and the personal context in which someone uses their device. Conclusions & Implications: Although the original aim of the project was to establish the user requirements of VOCA design, the data indicate that the characteristics of the device cannot be considered in isolation. Those factors uncovered highlight questions about whether the design of communication aids is truly effective in meeting the needs of the people who use them. Based on these data, an initial specification for future device design is proposed. (Contains 2 tables, 8 figures, 4 quotes, and 3 notes.)