# Parallels in the sequential organization of birdsong and human speech

Posted on Sat 17 August 2019 in Birdsong

My new paper, "Parallels in the sequential organization of birdsong and human speech" was published in Nature Communications this past week (ReadCube link | DOI link). In it, we explore long- and short-distance sequential-relationships in birdsong and speech.

a-d UMAP projections of syllables from a single example bird from each species (Bengalese finch, California thrasher, Cassin's vireo, European starling). e-h Sequence-transitions between syllables from the same bird as a-d i-h Markov model abstraction of e-h

### Abstract¶

Human speech possesses a rich hierarchical structure that allows for meaning to be altered by words spaced far apart in time. Conversely, the sequential structure of nonhuman communication is thought to follow non-hierarchical Markovian dynamics operating over only short distances. Here, we show that human speech and birdsong share a similar sequential structure indicative of both hierarchical and Markovian organization. We analyze the sequential dynamics of song from multiple songbird species and speech from multiple languages by modeling the information content of signals as a function of the sequential distance between vocal elements. Across short sequence-distances, an exponential decay dominates the information in speech and birdsong, consistent with underlying Markovian processes. At longer sequence-distances, the decay in information follows a power law, consistent with underlying hierarchical processes. Thus, the sequential organization of acoustic elements in two learned vocal communication signals (speech and birdsong) shows functionally equivalent dynamics, governed by similar processes.