ABSTRACT

Language is a species-specific human skill supported by a dedicated neural substrate, usually located in the left hemisphere. Exposure to language in the critical period is a sine qua non for its development. In those who lack early language exposure, its development is not adequate, syntactic abilities being the most impaired. Acquisition of written skills requires specific learning. Specific culturally derived neural networks develop when written language is mastered.In polyglots, there is an overlap of functional and structural neural substrate in the left hemisphere for the two or more languages spoken, which is more evident when the competence in both languages tends to coincide. Signed language is a natural language expressed by signs. Its neurological bases overlap with those of spoken language. Braille reading is supported by a process that involves connections between somatosensory and visual areas that allow the conversion of tactile stimuli into linguistic stimuli.