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Auteur: Audrey BÜRKI

Co-Auteur(s): Marina LAGANARO, FAPSE, Université de Genève

The production of French 'non-schwa variants' as a window into aphasic patients' phonological planning?

Abstract/Résumé: The present research examined the scope of advance phonological planning in patients with phonological impairment, as compared with that of patients with phonetic impairment. It is usually considered that the minimal unit of phonological encoding in non-brain damaged speakers is the phonological word (“one lexical head, potentially grouped with some functional elements”, Christophe et al., 2004). Accordingly, during the production of sequences involving a determiner and a noun, the two words’ phonological forms are processed together. We tested the hypothesis that the unit of phonological planning may fall below this limit in patients with phonological impairment. We compared their ability to repeat French schwa words (cheval ‘horse’) preceded by the determiner mon/ma ‘my’ with that of patients with a phonetic impairment. In one condition, the prompt corresponded to the schwa variant. In the second, it corresponded to the non-schwa variant. We took advantage of the fact that in French, words with a schwa in their initial syllable are mostly produced with the schwa when uttered in isolation and often produced without the schwa when preceded by a determiner ending with a vowel. If some patients activate and process the determiner and the noun’s word forms successively rather than simultaneously, they should tend to pronounce these words as if produced in isolation, that is, with the schwa variant. Moreover pre-and post-prosodic boundary markers of this word by word planning should be found. Results first revealed that both groups of patients produced schwa variants when prompted to repeat a non-schwa variant in more than a third of the trials. Crucially, whereas these errors were contingent on the presence of a clear pause between the determiner and the noun for the group with phonological impairment, they were independent of such pauses in the group with phonetic impairment. This finding strongly suggests that the source of these “errors” is a reduced scope of phonological planning in patients with phonological impairment. Moreover, at least one patient in each group produced only schwa variants (independently of the prompt), which allowed us to carry out specific acoustic analyses on the schwa produced by these two patients in the two conditions. The duration of the schwa was much shorter in the non-schwa than in the schwa condition for the patient with phonetic impairment but did not differ as a function of condition for the patient with phonological impairment. This finding further shows that whereas the source of schwa insertions in the patient with Apraxia of Speech is phonetic, it originates during the process of phonological encoding in the patient with phonological impairment.