For as long as organized human civilization has existed, we have been able to use language in order to communicate and develop new ideas that are integral to the growth of the individual and the evolutionary success of our species. The components of language, however, are not unique to humans; there are many species of animals that, to a certain degree, can utilize and process language. In this context, language refers to the ability to communicate with others by utilizing a shared set of symbols or vocalizations to convey meaning. For example, honeyguide birds have adapted to interpret human calls in order to help them locate beehives, while house pets, due to domestication by humans, have evolved vocalizations such as barking or meowing to convey their emotional states (Gross). Yet, one of the most defining features of animals is that they are unable to completely emulate human language, or in other words, they are unable to speak like humans do. So why can’t animals utilize language at a comparable complexity to how humans can?
The key to answering this question lies in the idea of the combinatoriality, or the propensity to form various combinations, of different language components. In turn, this combinatoriality drives the complexity of human thought and language. Although animal and human faculties of communication share certain similarities, it is the extra step of being able to connect the many discrete facets of language and language processing that elevates human language above most other forms of animal communication.
To clarify, human language depends largely on a discrete combinatorial system, wherein a limited number of components combine to create a near-infinite amount of output. Its components consist of the abilities to comprehend and create phonology, syntax, semantics, and relies on our physiological development, suited towards language creation and processing. Together, these processes and phenomena create the opportunity for humans to produce language that ensures not just their survival, but their overwhelming success.
With regard to the first of these components, phonology, or the sound system of a language, animals exhibit varying degrees of success in emulating and understanding human phonemes. Dogs, for example, not only are able to understand commands that they have been conditioned to, but also respond to emotional content communicated by their associated humans (Gross). Most remarkably, an African gray parrot named Alex has been shown to be able to name things, request specific food items, and even ask a question in addition to being able to repeat human words and phrases (Gross). Even so, the complexity of phonological processing that animals are capable of pales in comparison to that of humans. Not only do humans understand phonemes, according to Steven Pinker in his book The Language Instinct, they are additionally able to take phonemes and “sample and permute” them in various ways to create morphemes, the building blocks of words. Additionally, humans can mentally delineate words in speech they hear by imagining a word boundary when specific phonemes that match word endings are heard. In this respect, humans can extend upon the general skill of phonology to create and understand complex language.
Traditionally, animal cognition theorists hold that the syntaxes of animal forms of communication follow the model of a finite-state language. This is essentially a theory of language which posits that language is a simple system of words that correspond directly to a state, and most animal forms of communication follow this one-to-one approach of sounds to meaning (Schlenker). Although complex syntactic structure, as opposed to phonology, does not seem apparent in species other than humans, songbirds, such as the zebra finch, have developed a remarkable number of the processes that young children use to learn language syntax. In fact, song learning for zebra finches, just like language learning for babies, can be represented as the product of the interaction of pre-dispositions and specific experiences (Bolhuis et. al). When zebra finches that were isolated from the rest of their flock attempted to sing, their songs were naturally found to be abnormal, although they retained some species-specific features that they were predisposed to retain. However, when other zebra finches were tutored with a song from an isolated bird, they were able to bring the song back towards more species-typical features. This evidence certainly draws parallels to the way that a child that grows up speaking an incomplete or a pidgin language can inject their own syntax into the next generation of the language, as was demonstrated by the divergence of ISL – a new form of Nicaraguan sign language – from NSL – the old version (Pinker). However, this comparison falters when considering that each succeeding generation of the isolated zebra finch returned the song closer and closer to the typical zebra finch birdsong. In reality, each generation of human creole language is different and tends towards creating a new language as opposed to repeating an existing one. In fact, humans can develop fluency in a language even when only experiencing an incomplete version of the language, as evidenced by a young American Sign Language speaker, Simon, who was able to pick up and correctly use verb inflections even when his parents often misused them (Pinker). Humans, seemingly unbound by a species-specific grammar that they are predisposed to gravitate towards, are thus able to develop the syntax of a language every generation, setting them apart from most other animals and their grammatical tendencies.
Another faculty of language processing that most people do not intuitively associate with animal language production is the comprehension of semantics; indeed, most animals directly associate the sounds of words or calls with a specific concept. For example, honeyguide birds in northern Mozambique collaborate with the Yao people in order to hunt for beeswax (Gross). The birds have a specific kind of call when they know the location of a bees’ nest and need a human helper to break it up (Gross). Similarly, the Yao use a specific call to indicate that they are ready to go honey hunting and need a bird to guide them to the nest (Gross). After the Yao break up the nest and collect the honey, the birds are free to feed on the beeswax. This shows that the honeyguide birds are able to associate the calls of the Yao tribe with the prospect of obtaining a reward of beeswax. In addition to this, some animals have taken the concept forward and are able to change their calls to add more or less information. A study of monkey calls reveals that they follow the informativity principle, essentially preferring the more informative of two similar calls as long as they are both true (Schlenker et. al). While humans can do all of the above, they are additionally able to comprehend abstract concepts and give them semantic meaning. Although monkey calls have been shown to be functionally referential, meaning that a certain call could provoke a specific response even when they weren’t in the process of actively experiencing the associated thought, none of the animals above have been observed to have calls for abstract ideas that were not emotional (Schlenker et. al). This once again differentiates human language ability from that of other animals: although animals can associate meaning with a sound and adapt their calls to change their meanings, they are not able to do so at the level of human complexity.
Finally, there are multiple physiological differences between humans and animals that have promoted the usage and development of language in humans. Granted, other species can also create vocalizations in ways that are meaningful to us; an Asian elephant named Koshik was able to reproduce up to six Korean words, producing formants, or the fundamental sounds that make up vowels, that match up with those of his trainer (Stoeger et. al). However, Koshik had to manipulate his trunk and tongue to create sounds not normally in the range of an elephant due to their unique physiology. Indeed, an explanation of the uniqueness of human language is that humans evolved along a phylogenetic line that branched off a long time ago from our closest ape cousins and thus had on the order of 350,000 generations to evolve language processing physiology (Pinker). The most evident of the physiological adaptations that took place was the lowering of the larynx, allowing humans significantly more room for articulation and, hence, the production of phonemes that are so integral to language (Ghazanfar et. al). Other adaptations aren’t as visible; studies of the human brain have led us to demarcate areas of the brain dedicated to higher-level language processing, such as Broca’s and Wernicke’s areas. However, using fMRI technology to monitor brain function, it has been determined that there are also subcortical structures dedicated to pre-processing input before sending it to the language processing areas. This solidifies the idea that language processing is prevalent across the brain in areas outside the traditional language centers (Kandel). Most importantly, using a technique called lesion analysis that distinguishes the function of a specific area of the brain due to a lesion, researchers have been able to determine that the processing of language depends on numerous distinct neural structures with specialized functions belonging to systems. (Kandel). This shows that humans do not depend upon a single point or structure in their brains to create language; rather, they synthesize all the information processed by these regions for a complete understanding of language (Kandel). All of these findings combine to suggest that humans, as opposed to animals, have more articulative freedom, processing power and safeguards against complete language loss due to their evolutionary dependence on language to survive.
In conclusion, it is important to acknowledge that many faculties of human language are not completely unique to humans. The key to understanding the sheer complexity of human language, though, is in recognizing that humans simply have more of a capacity to combine and manipulate the elements of language than animals. As a result, humans are able to create a multitude of possible linguistic outcomes that have culminated in the nearly 7,000 languages and forms of human communication that span the diverse and flourishing civilization we inhabit today.
Works Cited
Pinker, Steven. Language Instinct. HarperPerennial, 1995.
Kandel, Eric R. “Chapter 1: The Brain and Behavior.” Principles of Neural Science, by Eric R. Kandel et al., McGraw-Hill, Health Professions Division, 2000, pp. 5–17.
Ghazanfar, Asif A., and Drew Rendall. “Evolution of Human Vocal Production.” Current Biology, vol. 18, no. 11, 2008, pp. R457–R460., doi:10.1016/j.cub.2008.03.030.
Gross, Michael. “Talking with Animals.” Current Biology, 22 Aug. 2016, pp. R739–R742.
Schlenker, Philippe, et al. “What Do Monkey Calls Mean?” Trends in Cognitive Sciences, vol. 20, no. 12, Dec. 2016, pp. 894–904., doi:10.1016/j.tics.2016.10.004.
Bolhuis, Johan J., et al. “Twitter Evolution: Converging Mechanisms in Birdsong and Human Speech.” Nature Reviews Neuroscience, vol. 11, Nov. 2011, pp. 747–757.
Stoeger, Angela S., et al. “An Asian Elephant Imitates Human Speech.” Current Biology, vol. 22, no. 22, 20 Nov. 2012, pp. 2144–2148.