Inflectional morphology: evidence for an advantage of bilingualism in dyslexia

ABSTRACT

It has been shown that morphological skills are particularly enhanced in bilingual children, whereas they are compromised in dyslexics. The aim of this work is that of investigating how bilingualism interacts with dyslexia in a task measuring the subject’s morphological abilities, to verify if the advantage typically found in bilingualism arises also in presence of a linguistic pathology such as dyslexia. We administered a task assessing the ability to generate plural noun inflections of nonwords to 106 children: 24 Italian monolingual dyslexics (mean age 10;0 y.o.), 30 Italian monolingual typically developing children (10;1), 22 bilingual dyslexic children with Italian as L2 (10;4) and 30 bilingual typically developing children with Italian as L2 (10;2). Results point to a positive effect of bilingualism, which also extends to dyslexia, with bilingual dyslexics performing consistently better than monolingual dyslexics, approaching and even surpassing, as in the most difficult conditions, the performance of monolingual unimpaired children.

KEYWORDS:

• Bilingualism
• developmental dyslexia
• inflectional morphology
• benefits of bilingualism
• nonword pluralization

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes on contributors

Maria Vender, Ph.D, is a Postdoctoral Researcher at the University of Veronainvolved in the FP7 European Project AThEME, Advancing The European Multilingual Experience. Her research interests concern the investigation of linguistic and cognitive deficits in language and learning disabilities, focusing in particular on the relationship between bilingualism and developmental dyslexia.

Shenai Hu is an Associate Professor at the Department of Foreign Language Education, Xiamen University. She earned her Ph.D in Linguistics in the Autonomous University of Barcelona and the University of Milan-Bicocca. Her research interests are in the areas of child language, reading disorders and language disorders with a special focus on bilingual children. She is particularly interested in how aspects of language form - syntax in particular - interact with other aspects of language development.

Federica Mantione (Ph.D., University of Verona in Italy, 2016) is a Postdoctoral Researcher in the Department of Psychology and Cognitive Science at the University of Trento, Italy. She primarily studies the underlying causes of morphosyntactic difficulties in the language of children with learning disabilities (in particular, Developmental Dyslexia). She is also interested in cognitive adaptation to language variation phenomena measured by electroencephalogram (EEG) in sentence comprehension tasks.

Silvia Savazzi, Ph.D, is an Associate Professor at the University of Verona. She is the director of the Perception and Awareness (PandA) Lab. Her major research interest relates the study of perception and awareness in healthy participants and brain-damaged patients with visual field defects or neglect. In her research, she uses several techniques: behavior, electrophysiology (EEG), neuroimaging (EROS - fNIRS) and direct brain stimulation (TMS and intraoperative electrocortical mapping).

Denis Delfitto graduated in philosophy and linguistics at the Scuola Normale Superiore in Pisa. From 1990 to 2001 he was Associate Professor at the Utrecht University and from 1996 to 2001 he coordinated the syntax/semantics research group at the Utrecht Institute of Linguistics. Since November 2001 he is Full Professor in General Linguistics at the Department of Humanities of the University of Verona. His research interests include the systems of interpretation in natural language, language impairment and many topics in the philosophy of mind.

Chiara Melloni, Ph.D., is an Assistant Professor in General Linguistics at the University of Verona, Italy. She is a researcher in the FP7 European Project AThEME, Advancing The European Multilingual Experience, and conducts theoretical and experimental research on the formal and interpretive properties of the lexicon. Her research interests concern word formation and inflection, approached from a theoretical, comparative and developmental perspective.

Notes

1 According to Bialystok, Peets, and Moreno (2014, 182), the Wug Test developed by Berko taps morphological awareness since it ‘assesses children’s sensitivity to morphological structure in English’. However, whereas morphological awareness tasks imply conscious access to the morphemic structure of words and the ability to reflect on that structure and to manipulate it (Carlisle 1995), the original Wug Test and the noun pluralization task that we designed in this study seem to tap morphological processing skills more than morphological awareness and general metacognition in children. For this reason, we will refer throughout this paper to morphological processing or morphological skills, although it cannot be excluded that this task involves some sort of metalinguistic skill or conscious access to the morphemic structure of words (especially in a language like Italian and in older children exposed to literacy, as in our study).

2 It is worthwhile reminding that declension classes do not trigger morphosyntactic agreement within the noun phrase (for instance, in the noun phrase quest-o pirat-a ‘this pirate’ there is masculine gender agreement between the determiner and the noun, but they belong to two different declension classes).

3 It is worth specifying that this mild correlation was found across all subjects and thus independently from bilingualism; no effect of bilingualism was indeed reported for the two WM tasks that we administered, consistently with other studies reporting that bilinguals and monolinguals show a similar performance in WM tasks (Engel de Abreu 2011, amongst others; see Grundy and Timmer (2017) for a comprehensive meta-analysis on bilingualism and WM capacity). It follows that performance in the WM task cannot be held responsible for the advantage shown by bilingual children in our morphological task. Moreover, it must be noticed that the lack of WM advantages in this study, apparently at odds with the results of studies on executive functions (see for instance Jalali-Moghadam & Kormi-Nouri (2015) for a study on bilingual poor readers), could be due to the lower complexity of our tasks, which tapped directly the subjects’ verbal WM, without specifically addressing the other components of the EF, i.e. inhibitory control and cognitive flexibility (Diamond 2013). Finally, the fact that we found an advantage in the pluralization of nonwords but not in the forward and backward digit span is arguably due to the fact that these tasks rest on different abilities, morphological competence on the one side and memory on the other side.

Additional information

Funding

This project has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement no 613465.