Parallels of human language in the behavior of bottlenose dolphins

Abstract

Dolphins exhibit striking similarities with humans. Here we review them with the help of quantitative linguistics and information theory. Various statistical laws of language that are well-known in quantitative linguistics, i.e. Zipf’s law for word frequencies, the law of meaning distribution, the law of abbreviation and Menzerath’s, law have been found in dolphin vocal or gestural behavior. The information theory of these laws suggests that humans and dolphins share cost-cutting principles of organization.

Variable expression of linguistic laws in ape gesture: a case study from chimpanzee sexual solicitation

“…Compression is a particular case of the principle of least effort [ 13 ]—a principle that promotes the outcome that requires the least amount of energy to produce or achieve—and thereby promotes coding efficiency [ 14 ]. In communication, compression is expressed as pressure towards reducing the energy needed to compose a code but limited by the need to retain the critical information in the transmission [ 15 , 16 ].…”

“…syllables, words, calls) to be shorter or smaller [ 14 ]—with similar patterns found at different levels of analysis, for example in speech at the level of words [ 17 ] syllables [ 18 ], and phonemes [ 4 ]. As well as being found in human spoken, signed and written languages [ 2 – 4 , 8 , 10 ], Zipf's law of brevity has been identified in the short-range communication of diverse taxa: dolphins [ 16 ], bats [ 19 ], penguins [ 20 ], hyraxes [ 21 ] and various primates (macaques: [ 22 ]; marmosets: [ 23 ]; gibbons: [ 24 ]; Indri indri : [ 25 ]), as well as in genomes [ 7 ].…”

“…At the level of constructs, Menzerath's law states that 'the greater the whole, the smaller its constituents' [6,26,27]; for example longer sentences have words of shorter average length, and words with more syllables contain syllables of shorter length. Menzerath's law (and its mathematical expression known as the Menzerath-Altman's law) has been identified in human spoken and signed languages [26,28], genomes [29,30], music [31], and in the communication of dolphins [16], penguins [20] and primates (geladas: [32]; chimpanzees: [33,34]; gibbons: [24,35]; gorillas: [36]; Indri indri: [25]). While many studies focused on vocal communication, several have now explored these statistical regularities in gestural and signed domains.…”