In tune with nature: Human speech follows a rhythm that is also found in the animal kingdom

A recent study conducted by researchers from the Leibniz Center for General Linguistics, Humboldt University Berlin, the University of Regensburg, and the Institute of Advanced Studies at Aix-Marseille University has revealed that the rhythm of human speech follows a pattern also observed in the communication signals of numerous animal species. This finding was published in the journal Annals of the New York Academy of Sciences.

To investigate whether human speech rhythm is unique or part of a broader biological pattern, the researchers analyzed speech recordings from 48 languages across all inhabited continents. They compared this data with rhythmic information from various animal species, including fish, seals, and birds. The analysis focused on inter-onset intervals, which are the durations between contiguous segments of speech followed by a pause.

This metric is also utilized in research on animal communication signals, allowing for a direct comparison between humans and other species.

The study encompassed more than 100,000 such intervals and found a strikingly consistent duration of approximately 2 seconds across all languages, irrespective of their language family or the individual characteristics of the speakers. This consistency was observed regardless of the language's regional origin or the specific attributes of the individuals speaking them.

The researchers compared these findings with existing data on animal communication, which showed that the human speech rhythm falls within the range of temporal patterns described in various animal species, such as the Cape fur seal, brown meagre, and skylark.

The researchers speculate that physiological factors, such as respiratory rhythms, and cognitive limitations like working memory capacity, may contribute to the observed regularity in human speech rhythm. The study's findings suggest that the fundamental temporal organization of human communication might be rooted in mechanisms shared by humans and other animal species.

Susanne Fuchs, a senior researcher at the Leibniz Center for General Linguistics and co-author of the study, notes that when the speech rhythm is calculated using the same methods as in animal communication, there are significantly fewer differences between the languages examined on this timescale compared to smaller linguistic units like syllables.

This implies that biological factors likely play a significant role in shaping the rhythm of human speech. Co-editor Ludger Paschen of the DoReCo corpus emphasizes that the study highlights the value of language documentation data from low-resource and endangered languages in addressing fundamental questions about the nature of human language.