M.Sc Thesis

M.Sc StudentAbu Amneh-Abbasi Dalal
SubjectThe Effects of Bilingualism and Proficiency in Hebrew and
Arabic on the Spatio-Temporal Distribution of
Speech Processing
DepartmentDepartment of Medicine
Supervisor PROFESSOR EMERITUS Hillel Pratt
Full Thesis textFull thesis text - English Version


Bilingualism offers a unique opportunity to explore the potential influence of variation in early language experience on the shaping of brain function and structure and its potential for plasticity. A central question in cognitive neuroscience has been whether a bilingual speaker represents each language in different areas of the brain. The present study aimed to clarify the relationship between two levels of bilingualism in Arabic and Hebrew and brain representation by investigating 10 'real' bilinguals, who informally acquired Arabic and Hebrew from infancy and were highly-proficient in both languages, and 14 Arab 'partial' bilinguals, who formally learned Hebrew at the age of 8 or later and were less proficient in it.

The experimental paradigm consisted of two experiments, main and special-case experiments. The main experiment's paradigm included monolingual and bilingual pairs of words in Arabic and Hebrew, with different degrees of semantic and phonologic similarity between them. The special-case experimental paradigm included pairs of words in literary Arabic and spoken Arabic, again, with different degrees of phonologic and semantic similarity between them. The experimental procedure for both experiments included auditory presentation of the pairs and the participant's task was to respond whether the two words in a pair had the same meaning or not. We used the event-related potentials (ERPs) technique, which has the highest temporal resolution to follow linguistic processing. We analyzed the latency and amplitude of the three main scalp-recorded waveform peaks: N1, P2 and N400. The results indicated that these three ERP components were sensitive to the level of bilingualism. These results show that the age of acquisition, proficiency and learning modality of the second language leads to a clear division between real and partial bilinguals. In addition, the two distinct levels of bilingualism affect the spatio-temporal scalp distribution of first and second language differently. Moreover, the hemispheric lateralization of first and second languages is similar in the bilingual brain, but differs between levels of bilingualism. Finally, that the special case of literary and spoken Arabic (termed diglossia) is not a case of two languages but two varieties of the same language, as evidenced by brain activity indices.