Normal Language: Cognitive and Linguistic Models

Language is the “most human” of all cognitive abilities. Hence, understanding how our brains process language has intrigued neuroscientists since the first description of an aphasic patient by Paul Broca at the end of the eighteenth century. Much of our knowledge about language processing derives from the observation of signs and symptoms caused by brain injury, but normal language is also a topic of investigation among researchers, from Psycholinguistics to Computational Sciences. However, the exact nature of linguistic processing is yet to be fully understood. Oral language comprehension seems to be based on the auditory discrimination of word subunits, which vary depending on the language considered: stress units (English), syllables (French), mora (Japanese), and so on. These subunits must then be grouped and a selection mechanism has to discriminate among similar words to avoid ambiguities. Grammatical rules contribute to organize words (in their morphosyntactic aspects), and, finally, context and prosody give their contribution so that the listener is able to understand the content of discourse, as in a conversation. Language production relies on the phylogenetic development of a specific supra-laryngeal articulation mechanism under neocortical control, and also of a social competence now described as Theory of Mind (ToM). Language production starts with the mental generation of a message to be conveyed; this message has to be translated into grammatically encoded words. Grammatical encoding includes lemma selection, morphosyntactic composition, morphophonological and phonetic encoding, in a complex process at the end of which the message (words) is uttered by the speaker.

Keywords: Language processing, cognitive model, linguistic model, language comprehension, language production