Short description: To relate the origins of human language with contemporary cognitive neuroscience data, particularly with the area of aphasias.

Abstract:

In spite of the potentially significant contribution that aphasia knowledge can make towards understanding the origin of human language, limited interest has been observed in using the aphasia model to approach language evolution. Some authors (e.g., Bickerton, 2007) have emphasized that there are two most central issues in language evolution: (a) how did symbolic units (words or manual signs) evolve? (b) how did syntax evolve? It has been suggested that symbolic units (i.e. lexicon) and syntax (i.e. grammar) are the only real novelties in human communication systems, and are therefore the most important points to approach in a theory on language evolution. That is, a theory of language evolution should explain how the lexicon and how the grammar appeared in human history.



Aphasia is generally defined as the loss or impairment of language caused by brain damage. Different subtypes of aphasia syndromes are often mentioned in neurology and cognitive neurosciences, including Broca’s aphasia, Wernicke’s aphasia, conduction aphasia, amnesic aphasia, transcortical aphasia, etc. The exact number of aphasia subtypes depends on the particular classification, but usually between four and seven different aphasic syndromes are mentioned. Seemingly, this suggested diversity of aphasic syndromes has obscured the major and basic distinction in aphasia: there are only two major aphasic syndromes.

These two fundamental aphasic syndromes are associated with a disturbance at the level of the language elements (lexical/semantic) in the Wernicke’s aphasia, or at the level of the association between the language elements (morphosyntactic/ grammatical) in Broca’s aphasia. It has been further observed that these two basic dimensions of language (lexical/semantic and grammatical) are related to two basic linguistic operations: selecting (that means, the language as a paradigm) and sequencing (that means, language as syntagm). Lexicon and grammar not only depend on different brain circuitries and areas (temporal and frontal-subcortical), are impaired in different types of brain pathologies (Wernicke’s and Broca’s aphasia), but also are mediated by different types of learning (declarative and procedural)



It can be proposed that three stages in language evolution could be distinguished: (a) Primitive communication systems similar to those observed in other animals, including non-human primates; (b) initial communication systems using sound combinations (lexicon), probably appearing thousands and even millions of years ago, correlated with the enlargement of the temporal lobe; (c) complex communication systems including not only a lexicon but also word-combinations (grammar). Most likely, this last stage in language evolution is only observed in the Homo sapiens. Grammar probably originated from the internal representation of actions, resulting in the creation of verbs. Grammar, on the other hand, may represent the basic ability for the development of so-called metacognitive executive functions (such as abstracting, problem solving, temporality of behavior, etc).



Bickerton, D. (2007). Language evolution: A brief guide for linguists. Lingua;117: 510–526.

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Citation:

Ardila A. (2016). Evolution Of Language From The Aphasia Perspective. In S.G. Roberts, C. Cuskley, L. McCrohon, L. Barceló-Coblijn, O. Fehér & T. Verhoef (eds.) The Evolution of Language: Proceedings of the 11th International Conference (EVOLANG11). Available online: http://evolang.org/neworleans/papers/8.html