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The “tree-pruning hypothesis” in bilingualism

Tissen, Andrea and Weber, Sandra and Grande, Marion and Gunther, Thomas
The “tree-pruning hypothesis” in bilingualism . Aphasiology, 21(6-8), August, 2007, pages 548-557.


Background: The “tree-pruning hypothesis” (TPH) suggests that syntactic deficits in agrammatic production are highly selective: most patients have impaired tense inflection while their agreement inflection is preserved. The TPH states that the split-inflection tree is pruned at the tense node, which is why an obvious dissociation in performance exists between tense and agreement.

Aims: This study aims to determine whether the TPH applies to a bilingual individual by examining whether a dissociation in performance exists between agreement and tense inflection in the bilingual speaker's two languages: German and Luxembourgish. We expect the pattern of grammatical impairment to support the validity of the TPH in German and Luxembourgish.

Methods & Procedures: The participant examined in this study, AM, is a pre-onset balanced German-Luxembourgish speaker with Broca's aphasia and moderate agrammatism. We used a verb completion and grammatical assessment task to examine whether a dissociation in performance existed between tense and agreement in both languages.

Outcomes & Results: The results comply with the TPH. The agreement results produced by the participant were significantly better than the tense results in both German and Luxembourgish.

Conclusions: The results show a clear dissociation in each language as predicted by the TPH. This confirms that the TPH can be applied to both German and Luxembourgish.

EPrint Type:Journal (Paginated)
ID Code:1781
Conference:Clinical Aphasiology Conference: Clinical Aphasiology Conference (2006 : 36th : Ghent, Belgium : May 29-June 2, 2006)
Publisher:Taylor and Francis
Alternative Locations:
DOI or Unique Handle:10.1080/02687030701191952
Additional Information:Access to the full text is subject to the publisher's access restrictions.