Have you ever reflected on whether language is unique to the human race? Let us meet with Alex the Parrot, Ake & Phoenix the Dolphins and Kanzi the Bonobo.

take a step back and ask what we consider language to be in the first place

This question prompts us to take a step back and ask what we consider language to be in the first place. Even though language comes naturally to us and we use it effortlessly, we rarely think about what its nature is. Therefore, it seems inescapable to try to elucidate what we mean by language, to differentiate it from simple communication, and to describe its most basic characteristics.

Broadly defined, language is a system constituted by symbols, and the rules that dictate how to combine and use those symbols. One of the most salient, distinctive features of language as known in humans is syntax, which can be defined as the rules for word order. Syntax allows us to communicate our thoughts efficiently, and this is where the power of human language lies. To answer whether some animals are capable of acquiring language skills, efforts have been made to teach some syntax to a number of species. It is important then, to describe a number of the defining features of syntax.

1. Elements of syntax

This is one of the properties of language that allows us to construct an infinite number of sentences using a finite number of rules

The first characteristic is that language is a “discrete combinational system”, which means that words can be combined while retaining their individual meaning, there are no half words or mixed meanings when two words are put together. This in turn, allows more features to be possible.

Then, syntax possess “category based rules”,  that is to say, the rules that govern the structure of sentences are dictated by the different categories that words belong to, for instance, nouns, verbs, determiners and adjectives.

A third feature is that sentences are built around verbs, and verbs are in fact the central part of the sentence. This is called “argument structure” because the verb dictates how many elements (arguments) need to be specified in the sentence so that it makes sense grammatically, for example the verb “give” involves three elements: to give (one) something (two) to someone (three) as in ‘she gave him a kiss’.

Another important characteristic of language is that words can be grouped into words that have a semantic content and provide meaning, representing a thing in the most symbolic sense (content words) and words that comply with a syntactic function in the sentence (functional words), for example determiners and prepositions.

Another feature that has been offered a lot of attention is recursion, the capacity that language has that allows a sentence to contain more examples of itself, making it longer and longer, for example “john sold his car; Rob said that John sold his car; I heard that Rob said that John sold his car”. This is one of the properties of language that allows us to construct an infinite number of sentences using a finite number of rules.

2.Alex, Ake, Phoenix and Kanzi speaking

Alex was able to respond to questions, classify objects by colour and material, count to six

Many researchers in animal language have tried to teach some species a rudimentary form of language, in the hope of shedding some light onto the question of the uniqueness of human abilities to communicate as we do. Famous research was carried with an African grey parrot named Alex, bottle nosed dolphins Ake and Phoenix and the bonobo Kanzi.

Alex was trained during many years, and he learned a vocabulary of approximately 80 items, which included words for objects, colours, action phrases like “wanna go x”, the numbers from one to six and to respond “yes” and “no”. Alex was able to respond to questions, classify objects by colour and material, count to six, and he was capable of understanding when an object was absent or when it was the same or different as something else.

The research with bottle nosed dolphins involved two different variants: Ake’s language was gesture based, with the signs being given by the trainer standing outside the tank. Phoenix’s language was acoustic, and consisted in synthesized sounds like words delivered underwater though a speaker system. The vocabulary was the same, approximately 40 items that referred to objects in the water, actions that could be performed interacting with those objects (e.g. go over, go under) and modifiers of location and direction. During the training, the dolphins were taught to perform two kinds of actions through the commands given using their respective language. They had to interact with one object, or to transport one object into another.

The bonobo Kanzi learned symbols of a lexigram system (a system of symbols or figures representing words) simply by looking at the interactions between his mother and the trainers. Apart from combining lexigram elements to communicate, Kanzi was able to understand English utterances spoken to him by his caretakers. For this reason, part of the project focused on comparing Kanzi’s knowledge of English with that of a two years old human child named Alia. When given commands in English, Kanzi had a performance that was similar to Alia’s.

the sophisticated structure of language that allows an infinite array of words and meanings is something that cannot be found in non-human animals

This body of research shows that all these animals were capable of using discrete combinations; they learned that different symbols stand for different objects or actions and these symbols can be combined in a string of few elements. However, the sophisticated structure of language that allows an infinite array of words and meanings is something that cannot be found in non-human animals.

Only humans have the capacity to exploit a sophisticated syntax that allows endless possibilities of combinations of discrete units (words) to convey meaning

One proposed view on the different communicational capacities that separates humans from other species can be illustrated with the distinction between broad and narrow language faculties. Broad faculties are perceptual and cognitive abilities that, although used in language, are also involved in many other cognitive tasks like reasoning and decision making. These faculties can also be shared with other non-human animals. On the contrary, narrow faculties are uniquely used to comprehend and produce language and are not shared with non-human animals. The fundamental components of these narrow faculties are grammar and syntax, and special importance is given to recursion, which is theorized as being the key element that distinguishes human language.

Others argue that to say that recursion is the single most important aspect of language that separates us from non-human animals is as incomplete answer, and go on to mention many other aspects that make human language unique, namely phonology, morphology and many aspects of words. Moreover, the sheer amount of words itself that are found in an average human lexicon, around 50.000, is an extraordinary human feature, all of these words meaning concrete things and having to be learnt.

So although some animal species could be capable of showing some rudimentary aspects of syntax (through human teaching, as in the case of dolphins or naturally like songbirds), this is as far as animal language complexity can go. No animal has shown the use of recursion or other fundamental features. Language as understood as a complex system of symbols and rules it is uniquely human. Only humans have the capacity to exploit a sophisticated syntax that allows endless possibilities of combinations of discrete units (words) to convey meaning.