Linguistic and emotional prosody: A systematic review and ALE meta-analysis

Prosody is a cover term referring to the melodic aspects of speech, with linguistic and affective (a.k.a. emotional) meanings. This review provides an overview of linguistic and affective prosody, evaluating two hypotheses on healthy individuals' linguistic and affective prosody. The first hypothesizes that the biological nature of affective prosody triggers activations unrelated to language (biological hypothesis), and the second that the aspects of affective prosody have been grammaticalized, i.e., incorporated into the language (linguistic hypothesis). We employed a systematic ALE metanalytic approach to identify neural correlates of prosody from the literature. Specifically, we assessed papers that report brain coordinates from healthy individuals selected using systematic research from academic databases, such as PubMed (NLM), Scopus, and Web of Science. We found that affective and linguistic prosody activate bilateral frontotemporal regions, like the Superior Temporal Gyrus (STG). A key difference is that affective prosody involves subcortical structures like the amygdala, and linguistic prosody activates linguistic areas and brain areas of social cognition and engagement. The shared activations, therefore, suggest that linguistic and affective meanings are combined, involving shared underlying brain connectivity mechanisms and acoustic manifestations. We suggest that the traditional distinction between linguistic and affective prosody may be overly rigid. Much like speech, lexicon, and grammar-domains that convey affective, social, and linguistic meanings without explicitly reflecting separate categories-prosody, too, functions as a system interfacing with affective, social, and linguistic domains. We conclude by proposing a novel blending hypothesis: prosody should be viewed as an integrated system that serves both affective and linguistic functions.