Gelada vocal sequences follow Menzerath’s linguistic law

Abstract

Identifying universal principles underpinning diverse natural systems is a key goal of the life sciences. A powerful approach in addressing this goal has been to test whether patterns consistent with linguistic laws are found in nonhuman animals. Menzerath's law is a linguistic law that states that, the larger the construct, the smaller the size of its constituents. Here, to our knowledge, we present the first evidence that Menzerath's law holds in the vocal communication of a nonhuman species. We show that, in vocal sequences of wild male geladas (Theropithecus gelada), construct size (sequence size in number of calls) is negatively correlated with constituent size (duration of calls). Call duration does not vary significantly with position in the sequence, but call sequence composition does change with sequence size and most call types are abbreviated in larger sequences. We also find that intercall intervals follow the same relationship with sequence size as do calls. Finally, we provide formal mathematical support for the idea that Menzerath's law reflects compression-the principle of minimizing the expected length of a code. Our findings suggest that a common principle underpins human and gelada vocal communication, highlighting the value of exploring the applicability of linguistic laws in vocal systems outside the realm of language.communication | language | primate | Menzerath | Zipf

Polysemy and brevity versus frequency in language

“…Such robustness provides support to Zipf's hypothesis that these laws originate from abstract principles, e.g., functional pressures (least effort as he would put it), that are consistent with modern formalizations as a compression principle for the law of abbreviation [12,40] or a biased random walk over the mapping words into meanings for the origins of Zipf's meaning frequency law [13]. This theoretical approaches strongly suggest that it might be possible to provide a coherent and parsimonious explanation for the laws we have examined in this article and other laws such as Zipf's law for word frequencies [44] or Menzerath's law [45]. The need for an abstract standpoint is not only suggested by our analyses but also by patterning consistent with these laws in human language in different conditions, e.g., sign language [46], Kanji or Chinese characters [47,48], and also in animal communication [12,49,50].…”

Emergence of linguistic laws in human voice

“…In acoustics, spontaneous speech indeed tends to obey this law after text segmentation82, and has been found also in other non-human primates2881. Here we can test brevity law in essentially two different ways.…”

Do penguins’ vocal sequences conform to linguistic laws?

“…Quantitative linguistics is directing increasing research effort towards the identification and study of universal statistical patterns, known as 'linguistic laws', occurring in human, animal and artificial communication systems [1][2][3]. Among these, of particular importance are Zipf's Law of Brevity and the Menzerath-Altmann Law.…”