The aim of this workshop is two-fold. First, it aims to establish a research community focused on design and evaluation of synthetic speech (TTS) interfaces that are tailored not only to goal oriented tasks (e.g., food ordering, online shopping) but also personal growth and resilience promoting applications (e.g., coaching, mindful reflection, and tutoring). Second, through discussion and collaborative efforts, to establish a set of practices and standards that will help to improve ecological validity of TTS evaluation. In particular, the workshop will explore the topics such as: interaction design of voice-based conversational interfaces; the interplay between prosodic aspects (e.g., pitch variance, loudness, jitter) of TTS and its impact on voice perception. This workshop will serve as a platform on which to build a community that is better equipped to tackle the dynamic field of interactive TTS interfaces, which remains understudied, yet increasingly pertinent to everyday lives of users.