The debate whether animals have language spans millennia, with opponents and proponents from academic celebrities such as Noam Chomsky and Francine Patterson to long-gone philosopher and theologian figureheads such as Porphyry, Celsus, Plutarch, Aristotle, Thomas Aquinas and more.
Chomsky and, to a lesser extent, the Stoics, advocate for the uniqueness of human language and reason, although the definitions of these terms remain elusive (and often circular). Not surprisingly, we know a lot about human languages but there is no general unified theory that brings together that knowledge in to an elegant mathematical formula, to which we can point and declare, "This is language!" (Artificial Intelligence models, however, may be a step in that direction.)
Chomsky's theory of Universal Grammar proposes that humans possess an inherent language faculty that enables them to generate and comprehend language based on underlying linguistic principles. He asserts that language is a distinct human characteristic rooted in intricate syntactic structures and recursive rules. In the context of animal language, Nim Chimpsky, one of the earliest chimpanzees taught sign language (preceded by Washoe), played a significant role. Herbert Terrace, who aimed to challenge Washoe's linguistic abilities, taught Nim. Terrace explicitly invoked the name of the renowned linguist Noam Chomsky, known for his work on "universal grammar" and his firm belief that animals lack language. This connection is evident in Chomsky's recent book co-authored with Robert Berwick, titled "Why Only Us." Terrace also published a book with a similar stance, "Why Chimpanzees Can't Learn Language and Only Humans Can" in 2019. Both works highlight Nim as compelling evidence that non-human primates are incapable of language. Notably, after the research concluded, Nim was transferred to a pharmaceutical laboratory and later relocated to a shelter, where he passed away at the age of 26.
In contrast, figures like Francine Patterson, who worked extensively with Koko the gorilla and long-gone people like Porphyry, Celsus, Plutarch, and Aristotle have suggested that animals possess forms of communication that can be considered language-like. They advocate for the idea that animals exhibit complex and meaningful communication systems, albeit different from human language in terms of complexity and syntactic structure. Francine Patterson's work with Koko, an extraordinary gorilla who learned sign language, demonstrated the potential for non-human primates to acquire and use symbolic communication. Koko's ability to express her desires, feelings, and understand human speech supports the notion that animals can exhibit language-like abilities. She understood more than 2,000 spoken human words, far more than Nim’s 125 signs. For a while Koko lived with another gorilla Michael who knew 600 signs, learning some of them from Koko. Michael would used the signs not only to describe objects, but also to communicate emotions, dreams and memories, and even to tell lies. One of the memories he conveyed with signs was the murder of his mother by poachers in Cameroon when he was still very young.
Have humans, and only humans, developed a unique biological tool known as "language" through the course of evolution? Has language played a crucial role in elevating us to the top of the predator hierarchy? Do we possess a distinct verbal ability that can be seen as a special gift, or is it, as depicted in various cultural creation stories, viewed as a "curse" by the gods (e.g. The Tower of Babel story in the Old Testament)?
The debate over what language really "is" and if it is uniquely human is ongoing. Researchers are daily revealing the genetic and neural processes of the brain to better understand this complex system.
In spite of the academic debates, there is no doubt that the intricacies of the system we refer to as "language" should leave us in awe. Language enables us to receive and send sensory symbols, process them, and transform them into interpretations and predictions regarding their significance to ourselves and others.
Indigenous hunter-gather-trader peoples, such as the Shoshone Sheep Eaters of the Greater Yellowstone area, didn't waste time debating nuanced definitions of "language". Instead, they watched and listened to animals communicating in the real world; furthermore, they actually spoke to other creatures using "animal language" to alter their behavior (e.g. for hunting). Survival has little to do with the ivory towers of academic debates. If you want to learn another human language, you can't just pick up a dictionary of that language. You ultimately have to dive in to the deep end with other speakers of that language and try speaking it as best you can and watch how they respond. If you want to be an animal linguist, the same is true.
To comprehend the communication of animals, whether in the wilderness of Yellowstone or in one's own backyard, requires attentive listening and an earnest attempt to communicate with the creatures being studied. You don't need to be a linguist in order to begin understanding animal communication, but we hope the below primer brings you further insights in your journey.
“The Sheep Eaters [a native american tribe]…were complete masters of what is called the cabalistic language of birds and beasts, and can imitate, to the utmost perfection, the sounds of birds, the howling of wolves, and the neighing of horses, by which means they can approach, by day and night, all passers-by.”
A. Ross, Fur Hunters of the Far West (1855)
Language as a Functional System
While language has traditionally been considered a human attribute, recent studies and advances in systemic-functional linguistics (SFL) models have opened up new avenues for exploring the communicative systems of various animal species. Systemic-functional linguistics, developed by Michael Halliday (albeit for human language study), offers a powerful framework for analyzing language as a social semiotic system. It emphasizes the functional aspects of language, highlighting how language serves different social functions and contexts. Applying this framework to animal communication helps us understand the rich linguistic diversity that exists beyond the realm of human language.
Animals use a wide range of communicative systems, including but not limited to vocalizations, gestures, facial expressions, body postures, and chemical signals. These systems serve various functions such as mating rituals, warning signals, territorial marking, and social bonding...again, to name just a few.
These systems serve a multitude of functions, ranging from hilarious mating rituals that put even the most dramatic political courtships to shame, to warning signals that make political campaign attack ads seem mild. And let's not forget about territorial marking—animals have their own creative ways of staking their claims, making politicians' speeches about protecting their turfs seem almost mundane. And we can't ignore the adorable social bonding rituals in the animal world, which can make even the most hardened politicians melt with envy. It's a wild world out there, and the animal kingdom has its own fascinating playbook of communication and social interaction
Just like human language, animal communication systems are context-dependent, meaning that their communicative acts are shaped by the social and environmental factors surrounding them. Show up at a political rally and you better know which party its for.
By studying animal communication through an SFL lens, we can frame their communication through three metafunctions that mirror the fundamental dimensions of human language: the ideational, interpersonal, and textual.
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The ideational metafunction focuses on how animals convey their experiences and represent the world around them. This is similar to the study of semantics in linguistics. As an example, bees perform waggle dances to communicate the location of food sources to their hive mates. These dances incorporate both spatial and temporal dimensions, allowing bees to share vital information about the distance and direction of the food source.
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The interpersonal metafunction explores how animals establish social bonds, express emotions, and maintain group cohesion. The linguistic field of pragmatics is involved in these types of questions. Take, for instance, the vocalizations of dolphins, known for their complex whistles and clicks. These sounds serve to coordinate group activities, convey emotions, and establish individual identities within the dolphin community. The linguistic field of "pragmatics" offers similar lines of inquiry.
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The textual metafunction deals with the organization and structure of animal communication. Often, this is what linguists are talking about when they refer to grammar and syntax. It is also the function of language that is unique to humans, with birds perhaps being the exception. In some bird species, elaborate songs function not only to attract mates but also to mark territory boundaries. These songs exhibit syntactic patterns and melodic variations that contribute to their effectiveness in conveying specific messages.
Moreover, SFL models also shed light on the role of context in animal communication (see section on "context" below). The situational context, such as the presence of predators or the availability of resources, influences the form and content of animal signals. Additionally, the social context, including the relationships between individuals, hierarchies, and group dynamics, significantly impacts the ways animals communicate with one another.
Systemic functional linguistics (SFL) embraces a holistic perspective on language, contrasting with reductionist. In SFL, language is viewed as a complex system, where the study of a particular aspect requires consideration of its relationships with other elements proposed by the theory. To comprehensively describe a linguistic category, it must be examined from three vantage points: from above (analyzing its meaning and impact within a contextual framework), from below (investigating how its function is realized in linguistic structures), and from the surrounding environment (examining its interactions with other linguistic elements). This trinocular perspective aligns SFL with the study of complex systems, emphasizing the interconnectedness and interdependencies within language.
Animal linguistics, examined through systemic-functional linguistics models, opens up a fascinating field of research that helps us grasp the intricate ways in which animals communicate, establish social bonds, and navigate their environments. It challenges the traditional boundaries of language and reminds us of the diverse and multifaceted nature of communication in the wild world.
Semantics
Language serves as a vast repository of interconnected meanings, and understanding how these meanings are organized is crucial for comprehending the intricate fabric of language. The linguistic field of semantics is all about how symbols (e.g. sound, gestures) encode meaning. Two fundamental linguistic concepts that shed light on this are semantic fields and semantic chains. These concepts provide valuable insights into how words and concepts relate to each other and form coherent networks of meaning.
Semantic fields refer to groups of words or concepts that are semantically related or connected by shared features. These fields can be thought of as conceptual territories where words belonging to the same field share a common underlying theme or idea. For instance, within the semantic field of "colors," we find words like "red," "blue," "green," and so on. These words are semantically linked by their shared characteristic of denoting colors.
Semantic fields are not rigid and static; they exhibit variations and subcategories. Within the broader field of "animals," there are subfields like "mammals," "reptiles," and "birds," each characterized by a set of distinctive features that differentiate them from one another. The boundaries of semantic fields may also overlap, as certain words can belong to multiple fields simultaneously. For example, the word "fish" can be part of the semantic fields of both "animals" and "food."
One such semantic field in bird communication is the field of "alarm calls." Within this semantic field, different alarm calls serve to communicate specific threats or dangers. For instance, in many bird species, there are specific alarm calls that are used to signal the presence of aerial predators such as hawks or eagles. These alarm calls are characterized by their distinct acoustic properties and patterns, signaling to other birds in the vicinity that there is a potential threat from above. The shared characteristics of these alarm calls form a semantic field, indicating the presence of an aerial predator. Within the broader semantic field of alarm calls, there may also be subfields or variations that correspond to different types of threats. For example, some bird species have specialized alarm calls for ground-based threats, such as snakes or mammals. These alarm calls possess different acoustic features and convey a different message, indicating the specific type of danger and prompting appropriate defensive behaviors. In this example, the semantic field of "alarm calls" encompasses a range of vocalizations that share a common purpose: to warn and alert other birds about potential threats. Each alarm call within this field possesses specific acoustic properties and characteristics that distinguish it from other types of vocalizations and convey a particular message related to the perceived threat.
Semantic chains, on the other hand, explore the associations and relationships between words and concepts beyond the confines of a single semantic field. They demonstrate how meanings are interconnected, allowing for the navigation of meaning between related words. A semantic chain represents a sequence of related words or concepts, where each word in the chain evokes the next through shared semantic features.
For instance, consider the semantic chain "cat - animal - mammal - vertebrate." Here, the word "cat" evokes the concept of "animal," which, in turn, evokes "mammal," and so on. Each word in the chain is linked to the next by shared semantic properties, such as "cat" being an example of an "animal" and "animal" being a type of "mammal."
Honeybees provide an example of semantic chains in the animal world. The waggle dance consists of a series of intricate movements and patterns performed by a foraging honeybee inside the hive. The dance encodes information about the distance and direction of the food source. The dance begins with the bee performing a straight section known as the "waggle run" on the vertical comb surface. The duration and intensity of the waggle run convey the distance to the food source, with longer runs indicating greater distances. Following the waggle run, the honeybee performs a series of "figure-eight" or "loop" movements. The angle at which the bee performs these movements relative to gravity represents the direction of the food source relative to the sun or other points of reference. The semantic chain within the waggle dance can be understood as follows: The initial waggle run evokes the concept of "distance," which then leads to the concept of "direction" conveyed through the subsequent figure-eight movements. The combination of these movements creates a chain of related concepts, allowing the communicating bee to convey information about both the distance and direction of the food source to other bees in the hive. By following the semantic chain within the waggle dance, honeybees are able to communicate vital information regarding the location of food sources to their fellow hive members. The sequential and hierarchical nature of the dance enables the transmission of detailed spatial information, demonstrating the interconnectedness of meanings within the communication system of honeybees.
Semantic chains help us understand how words relate to broader categories or hierarchies of meaning. They reveal the hierarchical structure of language and how words are organized in a network of interconnected concepts. By following a semantic chain, we can traverse various levels of abstraction and explore the relationships between words and concepts.
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Synonyms: Synonyms are words or expressions that have similar meanings or convey similar concepts. They are different words with equivalent or nearly equivalent meanings in a given context. For example, "happy" and "joyful" are synonyms as they both express a similar positive emotional state.
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Homonyms: Homonyms are words that have the same spelling or pronunciation but differ in meaning. They may or may not share the same origin. For example, "bank" can refer to a financial institution or the side of a river, representing two distinct meanings of the same word.
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Antonyms: Antonyms are words that have opposite meanings or convey contrasting concepts. They are words that are semantically opposed to each other. For instance, "hot" and "cold" are antonyms as they represent opposite temperature conditions.
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Hyponyms: Hyponyms are words or terms that belong to a broader, more general category. They represent subcategories or specific instances within a broader category. For example, within the category of "fruit," hyponyms include "apple," "banana," and "orange."
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Hypernyms: Hypernyms are words that represent broader or more general categories. They are superordinate terms that encompass multiple subcategories or specific instances. In relation to hyponyms, "fruit" would be a hypernym.
What we may think is a bird, for example, repeating the same sound could actually be a word with multiple meanings. the intended meaning is revealed when it is used in "context" (see below). If you don't understand the context, you will miss the meaning. [We don't know yet if birds, for example, make "sentences" with words with related semantic relationships, but studies of human brains and neural networks are revealing how neurons can represent semantic networks of words such as synonyms and antonyms - see this paper.]
The concepts of semantic fields and semantic chains demonstrate that words and concepts are not isolated entities but are intricately connected within a complex web of relationships. Exploring semantic fields and semantic chains deepens our understanding of how language represents the world and how meaning is constructed and conveyed through linguistic systems.
The Languages of Life website uses semantic "fields" to group various animal sounds together. Some examples include contact calls ("hey, this is me"), alarm calls, feeding calls, attraction calls, territorial defense calls, etc. At the top of each web page for a given animal, we provide a circular diagram with the basic semantic fields for that animal (see the black-capped chickadee page for example). From there you can click on a particular semantic field and be taken to actual real-world video or audio examples of animals "using" language for that semantic field. In contrast, very little is known about semantic "chains" in animal communication, but as researchers and astute observers continue to study animals closely, we will continue to learn more about how animals combine words in to chains of semantically-related meaning.
Context
It's common sense knowledge that words and sentences can be interpreted differently based on "context". For example, take the two phrases in the below diagram, one from a human and the other from a black-capped chickadee. In the first phrase, "I made her duck", the phrase could mean that I made dinner for someone or that I caused someone to move downwards in response to, for example, throwing a ball at her. Context will reveal the meaning intended by the person who spoke those exact words. The words themselves don't have meaning until they are "used". This is a key concept used in approaches to language such as systemic-functional linguistics: language gets its meaning in context. Following that line of thought, the common call heard by chickadees and for which they get their name (chick-a-dee) is often composed of four syllables or words (we don't know which to call them yet)...see below diagram. But anyone who hangs around chickadees knows that this "sentence" can be used in intense alarming contexts (e.g. when a predator is attacking) or in less antagonistic contexts (e.g. when calling to one another with no predator around). Whether this common chickadee phrase is true homonymy (i.e. same word with different meanings) or if there are subtleties that we aren't hearing but the chickadees know are different words...we don't know. But the point remains, similar sounding linguistic units can have different meanings, which makes context important to being an animal linguist. After all, to have a different sound for every possible meaning could be energetically inefficient when context can fill in the blanks.
The word "context" is a slippery word, so it is useful to define. The first, and perhaps most important point, is that context can involve all of the senses: sight, sound, touch, taste, and smell (and all of their variations such as the use of electrical fields to communicate). And all creatures have evolved different capabilities to "sense" the world around them. Birds, for example, can see light waves that we can't (ultraviolent) and hear in time scales we can't (higher resolution). Fortunately, humans have good senses and can, no pun intended, get a sense of the context that an animal is experiencing when they are communicating. Use all of your senses to learn how to speak the language of another creature.
But "context" isn't just about the real-world situation in which an animal is communicating. It definitely involves that aspect, but context can influence "meaning" in many ways. Here are three other ways to think of "context": linguistic, semantic, and situational.
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Linguistic context refers to the immediate linguistic features (e.g. sounds) in relationship to one another as they are produced, such as grammatical structures, word choices, and rhetorical devices (e.g. emphasis). Analyzing these features helps to uncover the speaker's intended meaning and stylistic choices. An example of animal communication at this level is bird song. Many bird species incorporate elements from the songs of other birds into their own repertoire. For instance, the nightingale incorporates snippets of other bird species' songs into its melodious repertoire, creating an intertextual dialogue that showcases its ability to imitate and incorporate various vocal elements. Another different example comes from honeybees who combine different movements to indicate the distance and direction of food sources to other bees in the hive. The specific movements and orientation of the dance convey precise information, acting as a text that the receiving bees interpret. As this example reveals, language doesn't have to be produced with sound, but can also be produced through body language (e.g. sign language).
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Semantic context explores the meaning of words and phrases within the animal's learned repertoire and how they contribute to the overall message. This level of analysis involves examining lexical choices, connotations, and semantic relationships between words to uncover layers of meaning. An example of animal communication at this level is the vocalizations of vervet monkeys. These monkeys have distinct alarm calls for different predators, such as eagles, snakes, or leopards. The semantic context of each call conveys specific information to other monkeys about the nature of the threat, enabling them to respond appropriately.
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Situational context takes into account the broader social and cultural factors that influence the production and reception of the text. Understanding the historical and cultural background, the intended audience, and the specific social circumstances in which the text was written helps to interpret its meaning accurately. A notable example is the communication between social insects, like ants, through chemical trails. When ants discover food, they lay down pheromone trails to guide their nestmates to the source. The situational context, such as the presence of food and the need for efficient resource exploitation, influences the initiation and use of these chemical signals. Ultimately, language is a tool for survival. And species learn and adopt "language" to survive, and then often share that "language" with others so as to survive as a social unit.
This approach highlights the importance of examining the communicative event you might be witnessing within its broader linguistic, social, and cultural contexts to arrive at a more nuanced understanding of its intended meaning.
The below chart is a summary of the topics discussed here and can serve as a quick reference to make you a better animal linguist, and to try and understand what they mean when they use their versions of language.
At the top of the diagram is a spectrogram displaying a series of chickadee alarm calls in the presence of a goshawk. This represents the "discourse" that was actually heard. It is the "conversation" that happened. It's language in "use" (not in a grammar book). A discourse is made up of subcomponents of language, such as phonemes (sounds without associated meaning, similar to how the brain processes images from the retina in to lines and boundaries before it puts those together into a shape that can be interpreted as a specific object). Phonemes can be combined together in to "words" (and even morphemes...e.g. "ed" in "walked"...that carry meaning). Words can be combined together in to phrases, sentences, clauses and larger units of meaning.
In the middle of the diagram is often what people mean when they say "context" - namely, the who/what/when/where/why of the communication event that is taking place. In other words, the context of the situation at hand. In fact, when interpreting animal communication this is an easy checklist to run through: who is involved (not just in plain sight), what are they doing (e.g. looking around nervously), where are they doing it (e.g. under cover of a dense bush), when are they doing it (e.g. time of day, weather)...put these together and you might be able to decipher the why they are making certain calls and therefore tease out the particular meaning of the words they are using. Nathan Pipelow gives a great example of red-winged blackbirds, who will often sit throughout a cattail marsh, repeating the same sounding phrase over and over and over again But, if they switch from repeating one sound to repeating a different short phrase, they are saying that a threat is nearby. And, here's the kicker: It doesn't matter what repetitive sound they start with or switch to. It only matters that they switch. In other words, the "change" in sound and not the sound itself carries the alarm meaning with it. It's not the "word" that conveys meaning, per se, but the switch in sounds that conveys meaning. [Sounds a little like grammar to us.] This is a great reminder that animal languages don't need to be like human languages, and that context is key to understanding why they are using a particular call.
At the bottom of the diagram is the context of culture. One way to think of this is that culture represents the “tribe” the communicator belongs to, from higher level society, to lower level sub-groups, and even down to an animal's individual peculiarities learned up until that stage of their life. For example, black-capped chickadees and mountain chickadees frequently live in different regional geographies but often cross paths. They have different dialects but probably don't have different "languages" (i.e. codes that aren't readily understood by one another). A nuthatch may have an entirely different language, but could still be able to understand some "words" from chickadees, such as their alarm calls (which often cause a nuthatch to stop in its tracks and look around for danger). This makes sense because they often live in the same context as black-capped chickadees and therefore share common threats.
So, how does the brain represent these different means and their associated words? This video and this paper and this paper offer suggestions on how neural networks in the brain create a representation of language used in context. It is fascinating to ponder that what we "perceive" as the meaning in a sentence, word, or phone call with a friend, is simply a set of neurons firing together.