You are walking on campus or sitting at a café and suddenly become aware that you are eavesdropping on a conversation that is taking place in two languages at once. Sentences may start in English and then switch to Spanish and then back to English again. If you are a bilingual speaker of Spanish and English this may come as no surprise but if you are a monolingual speaker of one of these languages alone, you may wonder how the speakers are able to move so easily from one language to the other. Not only can these bilingual speakers switch from one language to the other but they can understand each other and they rarely make errors of speaking the wrong language.

Although proficient bilinguals are impressively skilled, many adults find it difficult to acquire a second language past early childhood. The research in our lab examines each of these problems. How do bilinguals juggle the two languages without making errors? What enables adult learners to acquire a second language successfully? We use behavioral and neuroscience methods to investigate each of these issues. What we have learned is that even skilled bilinguals cannot easily turn off one of the two languages. Instead, both languages appear to be active and the interactions between them change not only the second language, but also the native language. We are particularly interested in how individuals develop the skill to control their use of the two languages and how speaking two languages may benefit cognition more generally.

The research in our lab focuses on the interplay between these aspects of bilingual language use, from multiple perspectives and using multiple methods. Below are some examples of our ongoing research collaborations.

Current Projects

A new hypothesis about second language learning (The fate of the native language in second language learning)

In the last decade of research on bilingualism, we have learned that the same neural networks that support the use of the native language also support use of a second language. The differences in activation or connectivity that often emerge, then, are more likely to reflect the increased cognitive resources that are required when the second language is engaged. That requirement may be responsible for the observed functional and structural changes in bilingual brains relative to their monolingual counterparts and may also be the basis for the documented advantages in the realm of cognitive control. But sharing the same neural networks may also explain why it is so difficult for bilinguals to switch off one of the two languages at will. Even if behavior appears to be controlled, recent experiments suggest that brain activity betrays the apparent ability to separate the two languages. At the same time, these shared neural networks may explain why the native language changes in response to second language use. We see these changes at the level of the grammar, where bilinguals alter their parsing preferences in the native language when they are immersed in a second language context, even if they continue to use the native language actively. We also see them in the simplest language tasks when bilinguals speak the name of a pictured object in their native language. The hypothesis being pursued in this work is that the ability to modulate the changes in the native language may predict success in new language learning.

Bilingualism, mind, and brain: An interdisciplinary program in cognitive psychology, linguistics, and cognitive neuroscience

In this NSF PIRE (Partnerships for International Research and Education) project, investigators at the Pennsylvania State University’s Center for Language Science and University of California-Riverside aim to develop an international network of bilingualism research to understand the nature of the bilingual mind and brain, the processes of bilingual language development, and the consequences of bilingualism for cognition. Through this project, training opportunities have been made available to undergraduate and graduate students, postdoctoral fellows and junior faculty, and subsequent research has targeted a wide range of bilinguals from the US and international sites in Asia and Europe, from young Hispanic children whose bilingualism may affect the development of literacy skills, to adult speakers of many different spoken languages, and deaf individuals whose bilingualism entails the use of sign language together with a written language.

Translating cognitive and brain science in the laboratory and field to language learning environments

Despite the importance of bilingualism and the increasing linguistic diversity within the US, many assume that speaking one language is the norm. Some worry that children will be confused by exposure to multiple languages, that language switching indicates pathology, and that the diversity associated with multilingualism undermines effective school instruction. Recent behavioral and neuroscience research demonstrates that bilingualism may change minds and brains to be more open to learning, more cognitively flexible, and more resistant to cognitive decline. This research reveals neuroplasticity that requires that we change assumptions about language learning. The evidence on bilingualism holds the promise to change attitudes towards child rearing, educational policy, immigration, and healthy aging. Yet there is a disconnect between the basic science and its application to learning environments. The goal of this project is to begin to translate the new research findings on the behavior and neuroscience of language learning to inform practice.

In this NSF funded PIRE project the Center for Language Science at Pennsylvania State University and Judy Kroll’s lab at the University of California-Riverside will, starting in April, 2016, partner with colleagues in Europe, Asia, Latin America, and in the US, to create a network that enables research in contexts where the form of language learning and language contact differ from the environments that have typically informed research to date.  Part of the PIRE grant will be transferred to UCR where there will be opportunities for graduate and undergraduate students to travel abroad to conduct research.  For information on the existing PIRE project at Penn State see  A new UCR PIRE website will be launched later this fall.

Prediction in language processing: Bilingualism, aging, and cognitive control

Whether we are sitting down with a favorite book or having to study a textbook for class, we are constantly using different strategies to understand what we are reading. For books or texts where there is a particular topic being discussed, young adult readers in particular have been shown to form expectations for what words or ideas they think will come up next. This project focuses on this type of meaning-related prediction in reading, and looks at different ways that language experience and changes in cognitive or executive function can influence this process. To do this, we record EEG or eye movement behavior while individuals read sentences for comprehension. We have found that individuals from different backgrounds (monolingual or bilingual, older or younger) use different strategies to understand  what they are reading. In particular, it appears that executive function skill supports predictive reading, but that it does so in different ways as we age and as we gain experience with multiple languages. In our current experimental work, we are investigating whether this relationship between prediction and executive function is different for language learners, for text that is unexpectedly humorous, and for reading contexts that either support or work against predictive strategies.

The behavioral and neural basis of codeswitching: Bilingual speech, executive control, and language processing

This project examines bilingual language processing from the earliest indices of word retrieval in the brain until the moment when speech is finally articulated. We are using a combination of EEG, behavioral experimentation, and corpus work with spontaneously produced bilingual speech to better understand how bilinguals regulate their languages in everyday conversation.  In our corpus work, we are examining the types of phonetic changes that are associated with cross-language activation during speech planning, and tracking the linguistic factors that seem to influence bilinguals’ decisions to switch languages at a given moment.  In our experimental work, we are using eye tracking to examine how these subtle phonetic changes affect the process of speech comprehension, and we are using EEG to ask how the neural signatures of language regulation relate to the presence of cross-language phonetic influence during articulation.


The work described above was made possible through the support of the National Science Foundation and the National Institutes of Health through the following grants: NSF OISE-1545900 to Judith Kroll, Paola Dussias, John Lipski, and Janet van Hell; NIH R21-HD082796 to JK and PD; NSF BCS-1535124 to JK and PD; NSF OISE-0968369 to JK, PD, and JvH; NSF SMA-1409973 to Megan Zirnstein, JvH, and JK; and NSF SMA-1409636 to Melinda Fricke, JK, and PD.