Clinical Linguistic and French Sign Language: A Model for LSF Acquisition and Sign Language Disorders

Caroline Bogliotti

Projet IUF 2017-2022 

My research activities seek to achieve an interdisciplinary synthesis between a psycholinguistic approach, a clinical linguistics approach and cognitive neuroscience that I now apply to French Sign Language (LSF). Since my recruitment as Associate Professor (University Paris Ouest Nanterre la Defense, in 2009), I decided to focus on LSF studies. LSF is little known by linguists. This « sign language » material provides a fertile ground for investigation from the perspective of theoretical and descriptive linguistics, psycholinguistics, clinical linguistics and cognitive neuroscience. With respect to sign language linguistics, the nature of certain units (such as manual and non-manual parameters which combine to form a sign) is still poorly defined. The challenge of my project is to provide empirical data with psycholinguistic paradigms, using objectifiable electrophysiological markers in order to clarify the linguistic nature of certain units in LSF.

There is a lack of research in psycholinguistics and clinical linguistics on LSF, both on language acquisition and language disabilities in LSF signing people. The long-term goal of my research is to fill this gap and to provide specific markers of language development and sign language disorders (specifically for LSF) for the clinical and scientific community.

To achieve this goal, many theoretical issues in linguistics must first be clarified. I shall attempt to resolve these questions through my expertise in psycholinguistics. The analysis of this visual-gestural language (vs. audio-phonatory languages) is of interest to examine the different linguistic theories describing vocal languages ​​(henceforth VL). Can we describe sign languages ​​(henceforth SL) with VL models?  Does a change in the language substance (i.e. gestural vs. voice modality) modify the language structure?Are the specific linguistic units in VL (i.e. phonemes) identical in SL? Too few linguists give us a clear answer on the phonology of signed languages, on the grammaticalization of the signing space and the morphosyntactic structures that are deployed, on the influence of the surrounding vocal language in the process of lexical creation in SL, on how to analyze iconic structures linguistically, etc. Similarly, psycholinguistics offers too few answers about the developmental trajectory of language, given that language development is constrained by mastering the motor skills of gross articulators (trunk, arms), then fine ones (hands). Other questions also arise about the impact of the gestural modality on cognition or neuronal architecture: is the brain circuitry involved in language processing in SL identical to that involved in the treatment of VL? Lastly, it is also unclear whether SL impacts neuroplasticity: is the emergence of the hemispheric asymmetry observed in the acquisition of a VL also observed for SL, and if so, what is its time course?

Thus, if we wish for SL to characterize language development and disorders from a linguistic perspective, we must first have a fine-grained linguistic description of LSF phonology, morphology, syntax, semantics. These questions have both theoretical and empirical implications, and an applied interest: this research presents a challenge for society because it has direct consequences for professionals and clinicians (teachers, speech therapists, psychologists and neuropsychologists) in terms of diagnosis and development of language tools. These tools allow them to provide support for learners and patients in language instruction or language and cognitive rehabilitation.

In the coming years, the overall aim of my research will be to achieve two broad objectives:

  1. A first fundamental objectivewill be to propose a model describing the various stages of the acquisition of LSF, based on multidimensional empirical data, namely behavioral and electrophysiological evidence.
  2. The second, more applied, objective will provide a tool for the evaluation and remediation of language in LSF.

[1]In this case, instructionmeans assistance with language acquisition. The majority of deaf children are born into hearing families. Therefore, these children do not have a native language, and must be helped in their early language acquisition / learning.