Language evolution and music evolution

Together with language, music is perhaps the most distinctive behavioral trait of our species. Different hypotheses have been proposed to explain why only humans speak and why only they perform music and, if both abilities are evolutionary related, how and why they eventually diverged. Human linguisticality and musicality are certainly biologically and behaviorally rooted in animal communication, cognition, and socialization. A hypothetical musilanguage must have constituted a transition stage from animal signal systems to the syncretic coexistence of coming-to-be language and music. Growing complexity of social networks and technologies essential for survival of Homo created the need to regulate social relations and secure effective transmission of important information, causing musilanguage to split into proto-music and proto-language, with different specialization (despite considerable overlapping of their usage functions). Proto-music focused on expressing emotional content through singing vocalizations (e.g., motherese) and rhythmic use of instruments (knapping). Proto-language focused on accurate and timely transmission of referential information. Further differentiation of musical genres, each forming its own repertory of expressions, turned proto-music into music. In parallel, proto-language evolved into language under pressure to continuously convey increasingly complex and dense information streams between growing numbers of participants - to accommodate demographic and technological growth. Increased prosociality promoted the emergence of more complex social structures and behaviors, cooperation, and codependency, directing music and language towards greater divergence and complexity.