Lexical plasticity in early bilinguals does not alter phoneme categories: I. Neurodynamical modeling

Area of Science:

• Neuroscience
• Psycholinguistics
• Computational Linguistics

Background:

• Bilingualism can influence lexical representation and phoneme perception.
• Previous research showed performance asymmetry in bilinguals' lexical decision tasks (LDTs) based on phoneme substitution.
• It remained unclear whether lexical changes impact phoneme categories.

Purpose of the Study:

• To investigate the neural basis of lexical representation in bilinguals.
• To determine if exposure to dialectal variations modifies phoneme categories or just lexical representations.
• To test the hypothesis that bilinguals store word variations without altering phoneme perception.

Main Methods:

• Developed a biophysically realistic neurodynamic model of neural networks for phonemic and lexical processing.
• Simulated a lexical decision task (LDT) and phoneme discrimination tasks.
• Conducted syllable discrimination tasks with Catalan-dominant bilinguals exhibiting LDT asymmetry.

Main Results:

• The neurodynamic model replicated the LDT asymmetry observed in bilinguals.
• Simulated phoneme discrimination showed equal performance for both phonemes, predicting no change in phoneme categories.
• Empirical syllable discrimination tasks confirmed that bilinguals could distinguish phonemes equally well, supporting the model's prediction.

Conclusions:

• Bilinguals exposed to dialectal word variations can incorporate these into their lexicon.
• Lexical storage of variations does not necessitate alterations in underlying phoneme categories.
• Neurodynamic modeling provides insights into the neural mechanisms of bilingual language processing.