The simultaneous production of two grammars: Evidence from bimodal bilinguals


  • Seyyed Hatam Tamimi Sa'd Purdue University
  • Ronnie B. Wilbur Purdue University



bilingual mind, bimodal bilingualism, psycholinguistics, sign language, spoken language


A debated issue in psycholinguistics is whether both languages are active in the bilingual mind that hosts them. We examined this issue in bimodal bilinguals, i.e., individuals competent in one spoken language and one sign language. Signed productions and story-telling data pertaining to declaratives, wh-questions, and negatives from Iranian bilingual speakers of Khuzestani Arabic and Sadat Tawaher Sign Language confirm that they produce two different grammars simultaneously, one via their vocal tract and the other on their hands. This finding provides support for these bilinguals’ double active representation of languages, suspension of articulatory constraints, lack of inhibition, and processing costs. 

Author Biographies

  • Seyyed Hatam Tamimi Sa'd, Purdue University

    Seyyed Hatam Tamimi Sa'd holds a PhD in Linguistics from Purdue University. His research interests lie in theoretical linguistics, syntax, semantics, gesture, language evolution, bimodal bilingualism, sign language, and human and non-human animal cognition. 

  • Ronnie B. Wilbur, Purdue University

    Ronnie B. Wilbur is Professor of Linguistics, Purdue University, USA. Her theoretical and experimental studies on phonology, syntax and semantics of sign languages have shown that sign languages have syllables comparable to spoken languages, and that nonmanual markers are controlled by the same semantic operators. She developed the Event Visibility Hypothesis (EVH), that event structure is iconically represented in sign verb structure. Her research includes American Sign Language (ASL), Croatian Sign Language (HZJ), Austrian Sign Language (OGS), and Turkish Sign Language (TİD).




How to Cite

Tamimi Sa'd, Seyyed Hatam, and Ronnie B. Wilbur. 2024. “The Simultaneous Production of Two Grammars: Evidence from Bimodal Bilinguals”. Proceedings of the Linguistic Society of America 9 (1): 5692.