Reem Khamis-Dakwar

Lexical processing in two language varieties: An event-related brain potential study of Arabic native speakers

Arabic diglossia is a sociolinguistic phenomenon in which complementary social functions are distributed between formal and colloquial varieties of a language. However, little is understood about the underlying neural representations associated with lexical processing in diglossia. Integrating neurophysiological measures into diglossia research has the potential to elucidate brain activations associated with processing the two language varieties. In this paper we will present current neuroscientific research related to lexical representation and processing in Arabic diglossia, to develop an agenda for further integrative work in neuroscience and Arabic linguistics.
We will present two complementary studies utilizing electroencephalography (EEG)
as a tool to investigate lexical and phonological levels of representation in Standard and Spoken varieties of Arabic. The first study examines the neurofunctional bases of codeswitching between Modern Standard Arabic (MSA) and Colloquial Palestinian Arabic (PCA). Six native speakers of PCA listened to sentences from three experimental conditions: grammatical sentences in MSA or PCA, sentences with a semantically anomalous final word, and sentences with code-switched final words. Sentences were presented auditorily in random order, and participants were asked to judge whether the final word was in the same language as the rest of each sentence. High density EEG recordings were obtained during the task, and Event-Related Potentials (ERPs) were derived from the continuous recordings through time-locked averaging of epochs starting at final-word onset for each sentence type. N400 amplitude increased with the presence of semantic anomaly in both MSA and PCA, whereas the codeswitching manipulation resulted in a variety of changes both earlier (N200) and later (P600) in the processing stream.
The second study used EEG to investigate the mismatch negativity (MMN) responses of native speakers of Levantine Arabic to switching between Spoken and Standard language varieties, while controlling for semantic, acoustic-phonetic, and phonological variables. MMN is a negative-going ERP that can be elicited in the absence of attentional processing. MMN studies have shown speech perception to be based on language-specific phoneme traces, with MMN elicited only when pre-existing traces are activated. Utilizing a passive-listening oddball paradigm, we presented eighteen participants with four real-word conditions: 1) PCA words with different meanings (PCA ħa? (right) – ħad (border); 2) PCA and MSA words with the same meanings (PCA ħa?, MSA ħaq (right); 3) switching between varieties and between meanings (PCA ħa?- MSA ħað (luck)); and 4) switching across languages (PCA fi:l (elephant): English feel). High-density EEG recordings were simultaneously acquired, and continuous recordings were subjected to time-locked averaging and montaging to derive ERPs. A significant MMN response was found in response to the phoneme category switch within language varieties. However, a significantly greater MMN response was found for variety shift (where the standard and deviant belong to two different language varieties but have the same meaning). These findings suggest that the switch between varieties has neurophysiological consequences over and above a phonemic category change.
Together, these findings point to future directions for neurophysiological investigations to elucidate the neural representation of aspects of language processing, language learning, and/or language varieties, in studies of diglossia and bilingualism.