How Bilingual Infants Cope with Code-Switching

Two weeks ago, the Learning Sciences Brown Bag Series hosted its first guest speaker, Dr. Krista Byers-Heinlein! Byers-Heinlein is an associate professor in the School of Psychology at Concordia University. 

Byers-Heinlein’s work offered great insight into early bilingualism. During her talk, Byers-Heinlein shared her work on how bilingual infants cope when adults code-switch or switch between two languages when speaking. As an example, a French-English bilingual might say, “le chien is brown” when talking about a brown dog. Here’s what she found…


1. Infants notice single-word switches as early as 8-months. 

With assistance from Esther Schott, Megan Mastroberardino, Eva Fourakis, and Casey Lew-Williams, Byers-Heinlein analyzed whether 8- to 10-month-old monolingual and French-English bilingual infants could detect single-word language switches in two studies.

In their first study, infants heard a sequence where the word change was either presented in the same language (“kitty book kitty book”) in another language (“kitty livre kitty livre”). Both monolingual and bilingual infants failed to notice the change.

In a follow-up study, infants were presented with similar conditions, except the switch occurred within a sentence rather than a word list. For example, they either heard “I want the livre” or “I want the book.” Because infants do not typically hear word lists, language switches within sentences represent more real-world code-switching. 

There was a drastic change in the results: both monolingual and bilingual infants noticed the word change. Importantly, infants only detected the difference between conditions when the altered word was presented within a sentence.


2. Location of the switch matters.

Prior research shows that adult bilinguals are slower to speak when asked to switch from one language to another. This processing cost occurs because bilinguals must inhibit one language and activate the other when switching. With collaborators Casey Lew-Williams and Elizabeth Morin-Lessard, Byers-Heinlein explored whether bilingual infants also have a processing cost in her third study. 

French-English bilingual adults and 20-month-olds saw two images on a screen, for example, a dog and a book. Simultaneously, participants heard one of two utterances depending on the condition (Figure 1). Participants either heard two sentences presented in the same language or different languages (e.g., either “I like that one! The dog.” or “I like that one! Le chien.”).


Figure 1. Participants either heard “Look! find the dog” or “Look! find the chien” with this image.


Byers-Heinlein and colleagues also assessed real-time processing by examining how long participants looked at an object after hearing its label. Participants had a more difficult time recalling words in the switched-language condition (“Look! Find the chien”), indicating a processing cost

Infants and adults process code-switching similarly and the location of the switch matters. Both infants and adults monitor their languages while listening, resulting in a processing cost, but only for switches that occur within a sentence (“Find the chien,” not “I like that one! Le Chien”)


3. Language mixing negatively influences word learning but not processing. 

Byers-Heinlein, Amel Jardak, and Casey Lew-Williams taught French-English bilingual 30-month-olds two novel words: teelo and walem. These 30-month-olds saw two common animals standing on blocks associated with the novel words (Figure 2). One novel word was presented in a single-language sentence (“Do you see the pig on the teelo?”) and the other in a mixed-language sentence (“Do you see the chien on the walem?”). 

Figure 2. With this image, participants either heard “Look! Do you see the pig on the teelo?” or “Look, do you see the chien on the walem?”


The toddlers were then shown the novel objects and asked to find the words they learned. The English-French bilingual toddlers only learned the word when presented in a single-language sentence (e.g., “Look! Do you see the pig on the teelo?”). 

Byers-Heinlein suspected that the toddlers did not learn the novel word in mixed-language sentences because there may have been a processing cost. Interestingly, however, toddlers correctly identified the target word in mixed-language sentences, suggesting no processing cost. Thus, language mixing did not influence toddler’s processing of the novel word but did impact their learning of the word. 


4. Code-switching is rare, but increases as children get older. 

With co-authors AJ Orena, Linda Polka, and Lena V. Kremin, Byers-Heinlein used unobtrusive digital recorders, Language ENvironment Analysis (LENA), to collect day-long, at-home recording of 21 French-English bilingual 10- and 18-month olds. 

Overall, code-switching was infrequent and changed across development. Although at 10-months parents only code-switched seven times per hour, by 18-months it increased to 26 times per hour!


5. Parents code-switch more between sentences than within sentences. 

The LENA recordings provided additional insight into where code-switching occurs in real-world environments. Parents were more likely to code-switch between sentences (“I like that one! Le chien), and this pattern was more pronounced at 18-months than 10-months. 


6. Parents strategically code-switch to enhance understanding and word learning. 

From the LENA recordings, Byers-Heinlein and colleagues found that 66% of parents code-switched to enhance their children’s understanding. For example, a French-dominant parent would follow “I wouldn’t eat that” with “Pas pour manger” to assist their child’s comprehension. 

Parents also code-switched to teach new words. For example, a parent taught the novel, French word singe for “monkey” by saying, “That’s a monkey. Un singe.” 


Going beyond… 

Critically, these findings only apply to French-English bilinguals. In the future, Byers-Heinlein plans to explore code-switching in “Spanglish” populations, where Spanish-English bilinguals are common. Spanish-English bilinguals may code-switch differently and more frequently than French-English bilinguals. Additionally, Byers-Heinlein and her students are studying bilingual storybook reading. 

Here at the University of Delaware, Dr. Giovanna Morini also studies code-switching, but with Spanish-English bilinguals. The Brown Bag Series afforded Byers-Heinlein and Morini the opportunity to interact, collaborate, and augment their studies. 

The Learning Sciences Brown Bag Series is very thankful to have Krista Byers-Heinlein as our first guest presenter. Please join us for our next presentation on Thursday, August 13, 2020, at 3:00 pm, as graduate student Haobai Zhang will share her work that explores gender differences in mathematics and reading achievement. 

Post by: Alexus Ramirez 

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