Roberto R. Heredia and Jeffrey M. Brown

Texas A & M International University










(Forthcoming: To appear  in The encyclopedia of linguistics. Chicago: Fitzroy Dearborn Publishers).

Speakers of more than one language (e.g., bilinguals) are known for their ability to code-switch or mix their languages during communication. This phenomenon occurs when bilinguals substitute a word or phrase from one language with a phrase or word from another language. To illustrate, consider the sentence, (1) I want a motorcycle VERDE. In this sentence, the English word “green” is replaced with its Spanish equivalent. A noteworthy aspect of sentence (1) above is that the Spanish adjective “verde” follows a grammatical rule that is observed by most bilingual speakers that code-switch. Thus, according to the specific grammatical rule-governing sentence (1) above, sentence (2) I want a VERDE motorcycle would be incorrect because language switching can occur between an adjective and a noun, only if the adjective is placed according to the rules of the language of the adjective. In this case, the adjective is in Spanish; therefore, the adjective must follow the Spanish grammatical rule that states that the noun must precede the adjective.

Traditionally, code-switching has been viewed as a strategy to compensate for diminished language proficiency. The premise behind this theory is that bilinguals code-switch because they do not know either language completely. This argument is also known as semi-lingualism, which underscores the notion that bilinguals “almost” speak both languages correctly. However, one concern with this account is that the notion of language proficiency is not clearly defined. It is not clear whether reading and writing language skills should take precedence over spoken language. This reliance on reading and writing is problematic because most bilinguals receive their formal education in one language, whereas a majority of their social interactions take place in the other language. So, when their reading and writing abilities are tested in both languages, the language in which bilinguals received more formal education will usually fare better.

Recent developments in psycholinguistic research has focused on how code-switching is a natural product of the interaction of the bilingual’s two languages. Early researchers viewed code-switching as evidence that the bilinguals’ two languages were organized in separate and distinct mental dictionaries. For example, a general finding throughout the literature is that bilinguals take longer to read and comprehend sentences containing code-switched words as compared to monolingual sentences. Apparently, this time consuming process is due to a “mental switch mechanism” that determines which of the bilingual’s two mental dictionaries are “on” or “off” during the course of language comprehension. This mental switch is responsible for selecting the appropriate mental dictionary to be employed during the comprehension of a sentence. Thus, for a Spanish-English bilingual speaking English, the English linguistic system is turned on, whereas the Spanish linguistic system remains off. However, if during the course of comprehending a sentence, a Spanish code-switched word is encountered, the mental switch must disable the English linguistic system, and enable the Spanish linguistic system.

Other psycholinguistic research is concerned with identifying some of the factors influencing the comprehension of code-switched words. Research shows that bilinguals comprehend code-switched words faster when there is phonological overlap between the two languages. For example, Chinese-English bilinguals take longer to recognise English code-switched words in Chinese sentences, but only if the English words contain initial consonant-consonant (e.g., flight) clusters, simply because the Chinese language lacks this phonotactic structure. Other important factors reported to influence the recognition of code-switch words include, context, phonetics, homophonic (e.g., words pronounced the same), and homographic (e.g., words spelled the same), overlap between the two languages.

Another current view suggests that language dominance (i.e., which language is used more frequently) plays an important role in code-switching. For example, Spanish-English bilinguals report more linguistic interference (code-switching) when they communicate in Spanish, their first-language, and little or no code-switching when they communicate in English, their second-language. In other words, these bilinguals code-switch more when they communicate in Spanish than when they use English. Empirical research supports these observations. Psycholinguistic evidence also suggests that bilinguals retrieve English code-switched words faster when they listen to Spanish sentences, whereas they are slower to retrieve Spanish code-switched words as they listen to English sentences. More interestingly, evidence also shows that code-switched words are actually retrieved faster than monolingual words, but only if the code-switched word is in English, and the language of communication is Spanish. These results suggest a reliance on the bilingual’s second-language as opposed to their first-language. How are these results explained? The general idea behind this view is that after a certain level of fluency and frequent use of the second-language, a language shift occurs in which the second-language behaves as if it were the bilingual’s first-language. In other words, the second-language becomes more readily accessible and bilinguals come to rely on it more. Thus, regardless of which language the bilingual learned first, the more active (dominant) language determines which mental dictionary is going to be accessed faster. This argument is reasonable since most bilinguals in the US, whose first-language is Spanish, obtain their formal education in English. Likewise, many of their everyday interactions involve the second-language. As a result, words and concepts in English, the second-language, become more accessible than words in Spanish, the first-language. Thus, code-switching is not the same for both languages. Rather, it depends on language dominance. During early stages of bilingualism, Spanish-English bilinguals rely on their first-language when they communicate in their second-language. As a result, bilinguals are more likely to code-switch to Spanish, when they communicate in English.  However, as the second-language becomes the dominant language, bilinguals rely on the second-language when they communicate in the first-language. In this case, bilinguals code-switch to English when they communicate in Spanish.

In short, code-switching may be indicative of difficulties in retrieval (access) affected by a combination of closely-related factors such as language use (i.e., how often the first-language is used) and word frequency (i.e., how much a particular word is used in the language). Finally, the notion that people code-switch as a strategy in order to be better understood and to enhance the listeners’ comprehension is another plausible alternative.

Roberto R. Heredia

Jeffrey M. Brown

Further Reading

      Heredia, Roberto R.,  “Bilingual Memory and Hierarchical Models: A Case for Language Dominance.” Current Directions in Psychological Science 10 (1997)

      Kolers, Paul,  “Reading and Talking Bilingually,” American Journal of Psychology 3 (1966)

      Macnamara, John, and Kushnir, Seymour, “Linguistic Independence of Bilinguals: The Input Switch,” Journal of Verbal Learning and Verbal Behavior 10 (1971)

      Lederberg, Amy R., and Morales, Cesareo, “Code Switching by Bilinguals: Evidence Against a Third Grammar,” Journal of Psycholinguistic Research 14 (1985)

      Li, Ping, “Spoken Word Recognition of Code-Switched Words by Chinese-English Bilinguals,” Journal of Memory and Language 35(1996)

     Myers-Scotton, Carol. Duelling Languages: Grammatical Structure in Code-switching New York: Oxford University Press, (1993)