Bilingual lexical access is an area of psycholinguistics that studies the activation or retrieval process of the mental lexicon for bilingual people.
Bilingual lexical access can be understood as all aspects of the word processing, including all of the mental activity from the time when a word from one language is perceived to the time when all its lexical knowledge from the target language is available.De Groot, A. M. (2011). Language and cognition in bilinguals and multilingual: An introduction. New York, NY, US: Psychology Press Research in this field seeks to fully understand these mental processes. Bilingual individuals have two mental lexical representations for an item or concept and can successfully select words from one language without significant interference from the other language. It is the field's goal to understand whether these dual representations interact or affect one another.
Bilingual lexical access researchers focus on the control mechanisms bilinguals use to suppress the language not in use when in a monolingual mode and the degree to which the related representations within the language not in use are activated. For example, when a Dutch-English bilingual is asked to name a picture of a dog in English, they will come up with the English word dog. Bilingual lexical access is the mental process that underlies this seemingly simple task: the process that makes the connection between the idea of a dog and the word dog in the target language. While activating the English word dog, its Dutch equivalent (hond) is most likely also in a state of activation.
History Early research of bilingual lexical access was based on theories of monolingual lexical access. These theories relied mainly upon generalizations without specifying how lexical access works.
Subsequent advancement in medical science has improved understanding of psycholinguistics, resulting in more detailed research and a deeper understanding of language production. "Many early studies of second language acquisition focused on the morphosyntactic development of learners and the general finding was that bound morphemes appear in the same order in the first and second language". In addition, "second language learners are also able to produce and process simple sentences before complex sentences (Pienemann et al. 2005), just like first language learners", of which there are 2 models proposed: serial search models and parallel access models. Serial search modelsForster, K. I., & Bednall, E. S. (1976). Terminating and exhaustive search in lexical access. Memory & Cognition, 4(1), 53-61. propose that when monolinguals encounter a word, they will look through all the lexical entries to distinguish whether the input item is a word or not; if it is, they will only retrieve the necessary information about that word (i.e., its semantics or orthography). Lexical access is accessed sequentially, with one item at a time. In contrast, the parallel access models approach Morton, J. (1969). Interaction of information in word recognition. Psychological review, 76(2), 165-178. asserts that multiple entries can be activated at once, which means that the perceptual input from a word would activate all lexical items directly, even though some of them might not be necessary. In this way, numbers of potential candidates would be activated simultaneously and then the lexical candidates which are most consistent with the input stimulus would be chosen. ResearchersGleason, J. Berko & Ratner, N. Bernstein. (1998) Psycholinguistics, 2nd edition. New York: Harcourt Brace. (Published November 1997). addressed that both the serial and parallel processes are used for lexical organization and lexical access.
Knowledge of monolingual access led to the question of bilingual lexical access. Early models of bilingual lexical access shared similar characteristics with these monolingual lexical access models;Thomas, M. S., & Van Heuven, W. J. (2005). Computational models of bilingual comprehension. Handbook of bilingualism, 202. the bilingual models began by focusing on if bilingual lexical access would be different from monolinguals. In addition, to study the activation process in a separate language, they also investigated whether the lexical activation would be processed in a parallel fashion for both languages or selectively processed for the target language. The bilingual models also study whether the bilingual system has a single lexicon combining words from both languages or separate lexicons for words in each language.
With the occurrence of widespread computational modeling, researchers extended the theoretical approaches for the studies of bilingual lexical access. The computational models are now an essential component for mainstream theories, for example, the models of Bilingual Interactive Activation (BIA) model,Dijkstra, T., Van Heuven, W.J.B., & Grainger, J. (1998).Simulating cross-language competition with the bilingual interactive activation model. Psychologica Belgica, 38, 177-196. the Semantic, Orthographic and Phonological Interactive Activation (SOPIA) model,Grainger, J. (1998). MROM-p: An interactive activation, multiple readout model of orthographic and phonological processes in visual word recognition. Localist connectionist approaches to human cognition, 147. and the Bilingual interactive Model of Lexical Access (BLMOLA).Léwy, N., & Grosjean, F. (1997).A computational model of bilingual lexical access. Manuscript in preparation. Most computational models need to specify all the vague descriptive notions used in the earlier models and force researchers to clarify their theories. Those revised models test the viability of the original theories by comparing the empirical results with data generated from the model. Computational models are also able to generate new testable hypotheses and allow researchers to manipulate conditions which might not be possible in normal experiments. For example, researchers can investigate and simulate the lexical access systems under various states of damage without using aphasic subjects.Neuroscience of multilingualism
Hypotheses The two most prominent theories on lexical access for bilinguals, Language Selective Access and Language Non-Selective Access, attempt to explain the process and stages of lexical activation and selection. These hypotheses focus on determining whether lexical candidates from different languages that share similar lexical features are activated when a word is presented.Dijksta, T. (2005). Bilingual visual word recognition and lexical access. Handbook of bilingualism psycholinguistic approaches, 54, 179-201. For instance, when the Dutch word work is activated, is the English word pork also activated? If the answer is "no", it might suggest that language selection happens before the recognition of a word and only the lexical information of the target language is selectively activated, in which case lexical access is language selective.Grainger, J., & Beauvillain, C. (1987). Language blocking and lexical access in bilinguals. The Quarterly Journal of Experimental Psychology, 39(2), 295-319. If the answer is "yes", it might suggest the other possibility that the recognition of a word is processed in parallel for both languages and the lexical information of both languages are activated, in which case lexical access is language non-selective.Kroll, J. F., & Tokowicz, N. (2005). Models of bilingual representation and processing. Handbook of bilingualism: Psycholinguistic approaches, 531-553. Research pertaining to lexical access has indicated that it is not achievable to completely suppress a known language.
Language-selective access Language-selective access is the exclusive activation of information in the contextually appropriate language system. It implies when a bilingual encounters a spoken or written word, the activation is restricted to the target language subsystem which contains the input word.
One interpretation is that bilinguals initially make a decision about the language of the word and then activate the appropriate language-selected lexicon. In this mechanism, an executive system directs the language switch for the input word. In earlier studies, researchersMacnamara, J., & Kushnir, S. L. (1971). Linguistic independence of bilinguals: The input switch. Journal of Verbal Learning and Verbal Behavior, 10(5), 480-487.Albert, M. L., & Obler, L. K. (1978). The Bilingual Brain: Neuropsychological and Neurolinguistic Aspects of Bilingualism. Perspectives in Neurolinguistics and Psycholinguistics. found that bilinguals can comprehend passages composed of words entirely from only one language more quickly than passages composed of words from both languages. They explain this result as an involuntary switch that happens when bilinguals comprehend passages with two languages. When comprehension procedures in one language fail due to the language contextually changing, then the switch mechanism will automatically direct input to another language system. Therefore, bilinguals are slower at reading mixed language passages than at single language passages because they must spend time switching languages. However, those studies failed to consider that the two languages might be activated simultaneously and there might be a later lexical competition in choosing which language information to use. The later lexical competition can also be used to explain why bilinguals spend more time understanding passages in mixed languages. However, other studies have found that there is no significant cost incurred by inter-sentential language switching and mixing. A 2010 paper showed that there was no cost to switching between languages when bilinguals read sentences for comprehension. Additionally, a 2012 paper found that when making metalinguistic judgments and performing non-comprehension based tasks, switch costs were evident, but there was no evidence to support the hypothesis that there is a cost at the switch site when bilinguals read a mixed sentence, indicating that under normal circumstances and given sufficient linguistic context, language switching does not incur a cost.
In studies that investigate whether lexical candidates from different languages are activated selectively or non-selectively during bilingual lexical access, there are two basic types of stimuli used: interlingual homographs and cognates. Interlingual homographs are words from two languages that are identical in their orthography but differ in their meaning or phonology; for example, the English word "room" is spelled identically to the Dutch word for "cream". Cognates are words from two languages that are identical (or very similar) in orthography and also have a large overlap in their meaning; for instance, the word film is a cognate in English and Dutch. Researchers used those types of stimuli to investigate if bilinguals process them in the same way as the matched control words which occur only in one language. If the reaction time (RT) of interlingual homographs is the same as the controlled monolingual word, then it supports the language-selective access hypothesis. If RT is significantly different for interlingual homographs than for the controlled monolingual word, it supports the language-nonselective access hypothesis.