From static features of sound production to speech-relevant vocal flexibility
Animal vocal signals can encode various information about the emitter, such as static (e.g. age, sex) and dynamic attributes (e.g. arousal, emotional valence). Acoustic allometry investigates in particular the relationship between acoustic characteristics of vocalizations and the signaler’s body size. While honest signaling entails accurate rendering of an animal’s body size through its vocalizations, evolutionary drivers of animal acoustic communication have shaped sound production apparatuses in ways that differ across species to varying degrees. Such anatomical adaptations inherently constrain vocal signals’ structure, and are necessary to account for when investigating the mechanisms and functions underlying species communication systems. However, acknowledging these constraints also have broader implications, in particular when investigating the cognitive underpinnings of speech-relevant traits such as vocal learning. The potential interplay between acoustic allometry and sound modulation illustrates how new theoretical frameworks can contribute to the discussion about the emergence of our own language.