This workshop explores the potential evolutionary connections between signals of positive affect and language. Historically, emotion has been seen as a relatively intractable research topic, especially in nonhuman animals. When emotion has been studied, negative emotions have typically been the focus due to the clear associations of negative emotions like fear and pain with survival and fitness. But recent studies have explored the existence and potential functions of positive emotions in animals (e.g., Nelson et al. 2022). And recent methodological shifts have made studying affective states easier. For example, thermal imaging cameras allow for direct measurements of physiological arousal (Mota-Rojas et al. 2021; Travain & Valsecchi 2021), hormonal assays allow for direct measurement of slower systems to be measured, and even behavioral measures have seen strong improvements - for example, machine learning used for categorizing vocalizations and the cognitive bias test providing a window into optimism/pessimism. Human language was once considered separate from emotional vocalizations, but recent research has revealed many ways in which emotion plays a role in the production and comprehension of modern language (Majid 2012). Similar shifts in the field of animal communication set the stage for this workshop. Nonhuman animal communications have historically been dismissed as inflexible and directly tied to an emotional state (see discussion in Seyfarth & Cheney 2003). However, recent data has shown that many species have flexible vocalization systems that reflect emotional states but are also flexible and referential (Fedurek & Slocombe 2011; Cheney & Seyfarth 2018; Bergman et al 2019; Townsend et al. 2020). Recent studies have also cataloged similar structures in vocalizations across taxa that are associated with positive social contexts like play (Ross et al. 2010; Schwing et al. 2017; Winkler & Bryant 2021). Positive emotions and playful interactions have been suggested to broaden the contexts, thoughts, and actions of an individual while at the same time building their personal and social resources (Fredrickson, 1998). Play, laughter, and shared positive emotions in humans have been shown to be effective in building social community, and nonhuman animal vocalizations during play may similarly support social cohesion. Play signals also present some of the best evidence of pretense and semiotic transformation in non-human species (Beckoff & Allen 1998). Positive emotions (such as those found in play) may also support flexible learning through optimism boosts, impacting future actions in the physical and social domains. Researchers working in non-human animals are just beginning to study these emotional responses, and this workshop would allow dissemination of early findings as well as foster theoretical and methodological discussions that would shape the direction of future research.