By Emily Leclerc | Waisman Science Writer
Each new language learning app boasts that they have cracked the code on the best way to learn a language but the research on what might be the best approach is still mixed. A new paper from the lab of Waisman investigator Margarita Kaushanskaya, PhD, professor of communication sciences and disorders at UW-Madison, provides evidence that suggests when trying to learn two languages, studying them both during the same session rather than separately might be the more beneficial strategy.
The field of education research has long been trying to determine what the best way is to present information to learners of all ages. There are a variety of methods and ideologies, some with more evidence than others. “The study of human learning has been grappling with these notions for a very long time,” Kaushanskaya says. “You could imagine clustering information in lots of different ways, but we aren’t sure what is the optimal way to get you the biggest bang for your buck.”
Two of the simpler methods are called blocking and interleaving. They can be compared to how someone might approach reading two books that they will be tested on later. Blocking would be reading one book in its entirety and taking notes on it and then reading the second book afterwards. “It’s like doing AAA, then BBB, then CCC,” says Sandra Sobus, previous member of the Kaushanskaya lab, author on the paper, and current graduate student clinician at Rush University. Interleaving is when you combine or mix together multiple tasks or learning objectives into one session. It would look like reading a couple of chapters of the first book, then a couple chapters of the second book, before returning to the first book again. The reader ultimately absorbs the same information just in two different structures.
The scientific literature has gone back and forth about whether blocking or interleaving is better for learning new languages. Some show blocking is more beneficial while others say the opposite. “Even within our lab, we sometimes found that blocking benefited learners and sometimes interleaving did. It really depended on the kind of information we were teaching,” Kaushanskaya says. So, inspired by Sobus’ deep interest in bilingualism and how individuals pick up two languages, the research team decided to investigate.
Their paper, “The effects of interleaving and rest on L2 vocabulary learning”, was recently published in the journal Second Language Research.
During the first half of the study, the research team found that when teaching native English speakers new vocabulary in German and Polish that interleaving the two languages was more effective than blocking them. Participants were better able to retain the new words when the German and Polish words were mixed together rather than taught separately. Interestingly, in the second half of the study when the researchers introduced a rest period in between teaching the German and Polish words in the blocked portion, they found that interleaving and blocking the information had similar effectiveness.
“My biggest takeaway is that the two clustering methods can both be successful, but there are conditions that make one more successful than the other,” Kaushanskaya says. “So, in situations where people don’t get a break, intermixing the two languages is a better way of presenting them to people and in the context of second and third language acquisition, that’s a pretty unique finding.”
There are a few theories as to why this new study shows that interleaving may be the more effective learning approach. One idea is that interleaving helps individuals practice dealing with the competition between languages. “When you are learning multiple languages, there’s always going to be competition between them,” says Emma Libersky, doctoral student in the Kaushanskaya lab and first author on the paper. “With interleaving you are getting a lot of practice managing that competition because it’s happening continuously.”
Another theory is that interleaving helps to highlight differences between the languages being learned. “Noticing the differences helps with long-term retention and accuracy,” Sobus says. “Blocking may facilitate the initial acquisition of a skill through repetition, but this may not lead to a deeper understanding of the distinctions.” The short break introduced in the blocking portion of the study did help to reduce the difficulty of that method but interleaving was still marginally more effective.
Discerning which method is more effective also has the potential to influence how languages are taught in schools. It could lead to the restructuring of lessons and curriculums and could aid in teaching students who are interested in learning multiple languages at one time.
This research has opened up several new questions and future research paths for the team. “Our big next direction for this work is to look at how blocked versus interleaved learning looks in children,” says Caitlyn Slawny, CCC-SLP, doctoral student in the Kaushanskaya lab and author on the paper. “We will be looking at Spanish and English bilingual children particularly.” The current study was only conducted with adults limiting its scope in understanding the development of language skills. The lab also has interest in looking at different combinations of languages and if interleaving remains the better method when the languages are more similar (like Spanish and Italian) or more different (like German and Chinese).
Kaushanskaya and her lab also want to study this more particularly in the context of individuals who may have struggles with language learning. “We work a lot with children who have developmental language disorder as well as individuals with autism,” Kaushanskaya says. “Understanding how to best cluster information for these individuals is an important next step especially if it differs from typically developing individuals.”
In the longer term, the research team hopes to use this study as foundational work to then begin to look at if a combination of the two methods might be more effective than only utilizing one. This has the potential to be beneficial for individuals across the disability spectrum. “Starting with blocked practice, where you focus on one thing at a time, can make learning feel easier at first, especially for individuals who tend to get overwhelmed easier,” Sobus says. “Once a basic understanding is established, switching to mixed or interleaved practice could help improve memory and understanding of the differences.”
This study was funded by F31DC021386 to Emma Libersky, a Hilldale Fellowship to Sandra Sobus, an Oros Bascom Professorship to Margarita Kaushaskaya, R01DC016015 to Margarita Kaushanskaya, and a center grant to the Waisman Center (U54HD090256).