Language is ubiquitous and vital in our world. Yet, do we really know what this phenomenon is? How would we recognise language if we encountered it in unusual circumstances, such as the search for extra-terrestrial life? Plus, how can we best delimit the study of language without an agreed upon approach to the concept? There are multiple proposals for what language consists of or requires. Linguist Hockett’s language design feature list is arguably the most extensive past treatment. But therein lies the problem: the definitional criteria are manifold and debated, encompassing a range of (often complex) features of various levels of import, from symbolic reference, to overt communicative intentionality, and to involvement of specific types of mental recursion.
One broadly, though not conclusively, agreed upon element is the consensus that language is unique to humans. However, it is questionable how we reached this consensus, when we do not know what language is. Additionally, there are conceptual issues involved in the two extant views on the relationship between language and other species. Both perspectives involve considerable limitations – the stark divide between language and non-human communication, or linear continuum from one to the other. Moreover, a definitional criteria list is not the only way to approach an understanding of what counts as language or account for typological diversity amongst the world’s recognised languages, let alone non-human communication. Plus, other species should not be discounted from the discussion of language, given the increasingly complex findings of their cognitive capacities and communication. We could be missing key parts of the language puzzle. Yet, even if we agree to move beyond this species dichotomy, the problem remains of exactly how to integrate non-humans into a discussion about language in a systematic and conceptually coherent way.
Therefore, this interdisciplinary work first explores other options to traditional definitions and the categorisation approach these stem from, Classical Theory, and instead proposes that Prototype Theory presents a helpful basis for conceptualising language and how it relates to non-human communication and cognition. Such a move reframes the question from ‘what is language’ to ‘what counts as language’, thereby creating the basis for a quantitative methodology to answer the question, instead of basing answers on subjective assumptions. This Prototype Theory based approach also yields a potential solution: that there is a probable overlap rather than a gap between language and non-human cognition and communication in terms of multiple feature continua, without recourse to a species analysis. This approach also enables us to reach an understanding of the features that are central to the language concept/prototype to progress awareness of this phenomenon and the diversity of recognised languages too.
The use of Prototype Theory for its macro application to this matter needs expansion. Hence, the dissertation explores not only the vertical and horizontal dimensions of the categorisation theory, with its hierarchical and family resemblance based graded typicality of features approach, but also builds in a third and fourth dimension. These dimensions cover the network of interrelated equivalent level concepts, like meaning, alongside context and the role of culture; as well as a dynamic aspect, given features evolve over time or change according to context. This dissertation also provides an outline procedure and hypothetical example to demonstrate how the framework may be applied in future investigations. In sum, both the study of non-humans as well as a Prototype Theory approach highlight the problems that co-relate, as well as form part of the solution to ultimately understanding the nature of language and language’s place in nature.