Neuroscientific Conditions of Becoming a Multilingual—— Finding a brain region governing grammar acquisition in a new language ——Information

Date: January 24, 2024, 11:00 ‒ 12:00
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Presenters

Department of Basic Science, The University of Tokyo
Kuniyoshi L. Sakai, Professor
Keita Umejima, Research Associate
Department of Linguistics and Philosophy, Massachusetts Institute of Technology
Suzanne Flynn, Professor (online presentation)
Institute for Language Experience, Experiment & Exchange (LEX Institute)Kenshi Suzuki, Representative director

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Main points

 We found a brain region governing grammar acquisition in a new language, when native
speakers of Japanese who had experience in English, Spanish, etc., were newly exposedto spoken sentences in Kazakh.
 This brain region governing grammar acquisition in a new language completely matchedwith the “dorsal left inferior frontal gyrus,” which is the region that the research teamhas long identified as the “grammar center” involved in the syntactic processes of firstand second languages.
 The present neuroscientific study clearly proved the “Cumulative-Enhancement modelof language acquisition,” which claims that the effects of acquiring multiple languages
would accumulate, leading to a deeper acquisition of the languages.

Summary

Professor Kuniyoshi L. Sakai and Research Associate Keita Umejima from the
Department of Basic Science, the University of Tokyo, in their joint research with Professor
Suzanne Flynn from the Department of Linguistics and Philosophy, Massachusetts
Institute of Technology, have identified the brain region governing the who, when, and whatfor grammar acquisition when exposed to a new language. This study has been realized withthe aid of Institute for Language Experience, Experiment & Exchange (LEX Institute) /Hippo Family Club (Tokyo, Japan; Representative director: Kenshi Suzuki).
Our research group recruited participants who acquired Japanese as their mother tongueand had experience in learning English, and made them newly acquire Kazakh in anexperimental setting that modeled natural language acquisition. Using an MRI scanner(Note 1), we investigated the neural processes during which the participants performed
grammar tasks that involved heavy syntactic loads. As results, we successfully specified
that the activations in the dorsal left inferior frontal gyrus (dorsal L. IFG) (Note 2) wereenhanced “for which participants (the who),” “during which phase of trials (the when),” and“for which sentence types (the what).”Professor Sakai, the corresponding author of this paper, has demonstrated that this brain
region functions as the “grammar center” for a first language (L1) and second language (L2).
The current findings revealed that the same grammar center also plays a critical role in theacquisition of a third language (L3) and fourth language (L4), providing neuroscientificevidence consistent with the “Cumulative-Enhancement model of language acquisition,”
which claims that the effects of acquiring multiple languages would accumulate, leading toa deeper acquisition of the languages. This hypothesis has been proposed by Professor Flynn,
a co-author of this paper, based on her behavioral experiments on language acquisition.
Based on the method of repeatedly hearing sentences through natural speech sounds, theLEX Institute/Hippo Family Club has continued their multilingual activities for several
decades. Our present discovery further promotes the findings of our joint research releasedin March, 2021 (https://www.u-tokyo.ac.jp/focus/ja/press/z0109_00003.html).

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Contents of presentation< Research backgrounds and issues in previous research >Many Japanese people suffer from the consistent problem that they hardly ever are able
to speak English, in spite of their continuous and intense study of English as a “foreign
language” in school at different levels, as well as at colleges/universities, and other formsof language schools. Speaking multiple languages is often considered to be a "special ability."
However, in many regions of Europe and other multiethnic countries in Africa and Asia,
multilingual environments are a commonplace. In these environments, the effort needed for
acquiring a new language is often perceived to be much less stressful. There is someprevious research that has investigated L3/L4 acquisition in behavioral experiments. In
addition, apart from the findings reported by our research group three years ago,
neuroscientific evidence concerning acquiring a new language such as L3/L4s is still scant.
The contribution of the neural substrates common to L1/L2 acquisition has also not been
sufficiently identified.
< Research contents >We recruited 31 volunteers in the age of 14-26, including students of the University ofTokyo, students of Sophia University, and members of the Hippo Family Club. All
participants acquired English as their L2, and half of the participants achieved proficiency
scores indicating novice or higher proficiency in their L3 (typically Spanish) in a listening
comprehension test. All participants were exposed to Kazakh (a member of the Turkic
language family, and a native language in Kazakhstan and neighboring countries) for the
first time in the experiments, where we conducted grammar tasks (Fig. 1) utilizing speechstimuli recorded by a native speaker. Without the explicit teaching of any of thegrammatical rules in Kazakh, we repeatedly presented the correct and incorrect examples
for the grammaticality of a sentence, as well as for subject-verb correspondences in a
sentence in the demo trials. We tested whether the participants were able to judge correctly
the grammaticality of new stimulus sentences by themselves in the test trials. Approval forthe experiments was obtained from the ethical review board at the University of Tokyo, andwritten informed consent was obtained from all participants.
Each of the Kazakh sentences we used included a main clause and a relative clause, where
each clause included a subject, a direct object, and a verb. The “man” included in eachsentence is either the Subject (S) or Object (O) in the main clause, and is either S or O in
the relative clause; from this perspective, each sentence is classified as being one of thefollowing four types of sentence structures. For example, under the OS condition, the “man”
is an Object in the main clause, and a Subject in the relative clause (denoted by square
brackets [ ] in the examples below). In the experiments, we mixed these four sentence types
and presented them in a completely randomized order.
1. Example English translation under OS: “We recognized a man [who knew John well].”
2. Example English translation under OO: “We recognized a man [whom John knew well].”
3. Example English translation under SO: “A man [whom John knew well] recognized us.”
4. Example English translation under SS: “A man [who knew John well] recognized us.”3 / 11In each task trial, we presented a sentence auditorily, and then presented a noun-verb(NV) pair. We tested the GR task, which required the participants to judge whether thesentence was grammatical or ungrammatical. We also tested the SV task, which required
the participants to judge whether the NV pair was matched with one of the two subject-verb(SV) pairs in the sentence structure or not. Based on the distributions of the accuracy rates
in the tasks, we separated the participants into two groups: Group I (16 participants, 7
women), consisting of those who had reached accuracy rates higher than 60% in the SV task
for both the OS and SO conditions, and Group II (15 participants, 7 women), consisting of
those who did not. Regarding these groups, we confirmed that the more proficient thebilinguals and multilinguals were in their L2/L3s, the higher their performance became intheir L3/L4s (i.e., Kazakh).
For each participant, the temporal sequence of trials was divided into four phases(quarters), the accuracy rates for Group I significantly increased from the first to fourth
quarters in the SV task under the OS and SO conditions (Fig. 2a), as well as under the OO
condition. In contrast, for Group II, the accuracy rates did not significantly change (Fig. 2b).
During the fourth quarter, Group I successfully performed all conditions except for the SS
condition in the SV task (Fig. 2c). In contrast, Group II was not able to acquire any of thesentence structures in any condition within the time window of our experiment (Fig. 2d).
Using functional MRI (fMRI) (Note 3), we measured the brain activations while theparticipants were performing the grammar tasks. The activations for Group I, whencompared with those for Group II, were significantly higher in the dorsal L. IFG andbilateral STG/MTG (Fig. 3a, left), as well as in the medial regions. When we focused on the
successfully performed conditions of OS, OO, and SO, activated regions were more localized
in the dorsal L. IFG and L. STG/MTG alone (Fig. 3a, right).
With regards to the phases of trials, we compared the brain activations during the final
fourth quarter with the initial first quarter for Group I, and observed focal activation in thedorsal L. IFG alone (Fig. 3b). In addition, we compared the activations under the OS, OO,
and SO conditions, which were successfully acquired by Group I during the fourth quarter,with those under the SS condition, and again observed focal activation in the same dorsal
L. IFG alone (Fig. 3c).
The fact that activation in the dorsal L. IFG was observed consistently indicates that thisregion, known as the “grammar center” of L1/L2, also plays a critical role in the grammar
acquisition for the L3/L4.
Moreover, we quantified the activation in the dorsal L. IFG during the presentation of the“Sentence” that preceded the tasks, and, interestingly, we observed significant correlations
against the accuracy rates for both the GR (Fig. 4a) and SV (Fig. 4b) tasks. In other words,
if we measure the activations in the dorsal L. IFG, we can actually predict the accuracy
rates for the subsequent experimental tasks.
The activations in the dorsal L. IFG were free from task difficulty or memory loads (socalled working memory), because larger activations were observed in the participants
indicating less difficulty in performance on these tasks. The dorsal L. IFG activations thus
should be reflecting successful building of sentence structures.
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< Social significance and future plans >In Japan, English skills of the Japanese people are continuously decreasing yearly,
although English has been a curricular subject, beginning in the elementary school
education. This is especially true with regards to the youngest participants, who are 18–20
years of age; their English scores are decreasing most significantly, shifting from “Moderate”
to “Low,” and further to “Very low” during the recent years (EF Education First Japan, Ltd.,
https://www.efjapan.co.jp/epi/regions/asia/japan/). Possible reasons for this decrease could
be that many Japanese people traditionally have studied English solely by relying on
memorizing individual words and learning grammar rules explicitly. It could be that we are
currently exposed to massive amounts of textual information such as in the SNS with rather
low or poor exposure to actual speech sounds. The results of the current research indicatethat even Japanese people can acquire any new languages by simply experiencing exposure
to speech in the target language. This clearly suggests the synergistic effect of acquiring
multiple languages simultaneously. This suggestion is consistent with the notion of “naturalacquisition” of languages, and raises questions for language education in general. For
further discussion, please see “Acquiring English without Studying: An Epoch-Making
Method Based on Brain Science (Japanese)” (Sakai, 2022, PHP Institute, Kyoto).
Another reason may derive from the underlying misconception of “teaching a foreign
language.” Wilhelm von Humboldt, the founder of the Humboldt University of Berlin andalso a linguist, concluded in 1836 “that one cannot really teach language but can only
present the conditions under which it will develop spontaneously in the mind in its own way.
[...F]or the individual, learning is largely a matter of Wiedererzeugung[reproduction/regeneration], that is, of drawing out what is innate in the mind” (Chomsky,1965). This idea is the basis of the “innateness hypothesis” of language acquisition proposedby the American linguist Noam Chomsky, and suggests a universal underpinning for all
natural languages. For evidence from neuroscience for this hypothesis, please see “Chomsky
and Neuroscience of Language (Japanese)” (Sakai, 2019, Shueisha International, Tokyo).
The Sakai laboratory of the University of Tokyo will continue to investigate and thus
reveal the mechanisms of the human brain underlying the creative aspects of language, andthe LEX institute will promote practical activities regarding multilingualism, contributing
to the realization of deep and meaningful communication among people across the world.

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Figure 1. Temporal events in a demo or task trial.
(a) In the demo trials, a Kazakh sentence [either grammatical or ungrammatical] was presented auditorily,
followed by an NV pair [either matched or mismatched with the two SV pairs in the sentence structure;underlined words denote such a mismatch]. In each NV pair, the noun (or pronoun) was presented always
without a suffix for the accusative case (e.g., adam for adamdï), and the verb was presented always with athird-person singular suffix in the simple past tense. The + / − sign presented simultaneously with a sentenceindicated its grammaticality/ungrammaticality, and the + / − sign with an NV pair indicated match/mismatch(see above). The sentence shown in the figure means “We recognized a man who knew John.” (b) In the task
trials, five Kazakh words (“Lexical list” in the figure) were presented auditorily; individual words translated
into English were visually presented. This Lexical list was followed by a sentence using all five words fromthe Lexical list. The participants chose a + / − button in a grammaticality task (GR task). An NV pair was thenpresented to the participants asking them to judge the correctness of matching (see above). Here again, theparticipants chose a + / − button in a subject-verb task (SV task).

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Figure 2. Proficiency improvement in Kazakh.
(a) Accuracy rates in the SV task during each quarter, shown for Group I, who met the criteria of more than
60% (the fourth quarter) in the SV task under both the OS (left) and SO (right) conditions. (b) Accuracy rates
in the SV task for Group II, who did not reach the above criteria. The rates remained at chance level under
the OS (left) and SO (right) conditions. (c) The d′-values for Group I (the fourth quarter), which weresignificantly above chance level at value 0 except for SS in the SV task. (d) The d′-values for Group II, none ofwhich were significant. Error bars indicate standard errors of the mean (SEM) for the accuracy rates and RTs,
whereas the error bars of d′-values indicate estimated variances. *p < 0.05.

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Figure 3. Activations related to groups, phases, and conditions.
(a) Focal activations observed in a direct comparison of the [Group I − Group II] contrast. During the Sentence
events, activations were mainly observed in the left inferior frontal gyrus (L. IFG) and superior/middle
temporal gyri (STG/MTG) under the OS, OO, SO, and SS conditions (left), or under the OS, OO, and SO
conditions (right), consistent with behavioral results (see Fig. 3c). (b) L. IFG activations for Group I, observedin the [4th quarter − 1st quarter] contrast. Activations in the [NV pair − Lexical list] contrast (abbreviated as
NV pair′) were averaged among OS, OO, and SO conditions. (c) L. IFG activations for Group I, further revealedby the [(OS + OO + SO) − SS] contrast during the fourth quarter.

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Figure 4. Brain activations related to the subsequent task performances.
(a) A correlation between L. IFG activations and accuracy rates in the GR task for all participants. Averaged
among the four construct conditions, the rates in the GR task became higher for the participants, whoshowed stronger activations in the [Sentence − Lexical list] contrast (abbreviated as Sentence′). The regionof interest (ROI) for this figure was determined by the activated region in Fig. 3c. (b) A similar correlation in
the SV task. Stronger L. IFG activations also predicted higher rates in the SV task.

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Related Information:
Multilingual people have an advantage over those fluent in only two languages.
UTokyo-MIT study measures brain activity while learning basic sounds, grammar rules of
unfamiliar language (April 1, 2021)
https://www.u-tokyo.ac.jp/focus/en/press/z0508_00173.html

Presenters

Department of Basic Science, The University of Tokyo
Kuniyoshi L. Sakai, Professor
Keita Umejima, Research Associate
Department of Linguistics and Philosophy, Massachusetts Institute ofTechnology
Suzanne Flynn, Professor
Institute for Language Experience, Experiment & Exchange (LEX Institute)Kenshi Suzuki, Representative director

Bibliography

Journal：Scientific Reports (Nature Portfolio Journal), published online on January 2nd.
Title：Enhanced activations in the dorsal inferior frontal gyrus specifying the who, when,
and what for successful building of sentence structures in a new language
Authors：Keita Umejima, Suzanne Flynn, Kuniyoshi L. Sakai*
DOI：10.1038/s41598-023-50896-6
URL：https://www.nature.com/articles/s41598-023-50896-6

Funding

This research was supported by funding from the LEX Institute, and by the Grant-in-Aid
for Challenging Research (Pioneering) (Nos. 21K18115) from the Ministry of Education,
Culture, Sports, Science, and Technology of Japan. This study had no conflicts of interests.

Glossary(Note 1) MRI scanner
Magnetic Resonance Imaging (MRI) is a technology for imaging brain tissue architecturesby measuring protons’ responses to the local magnetic field. MRI is broadly used as a method
to observe brain tissues from outside of the brain without causing any damage. For thispurpose, we use the MRI scanner, which is a medical equipment with superconductive
magnets that generates high magnetic fields (about 3 tesla). This MRI scanner is used for“fMRI” explained in Note 3.

10 / 11(Note 2) dorsal left inferior frontal gyrus (dorsal L. IFG)
The dorsal IFG (Brodmann’s area 44/45/6) are regions in the frontal lobe of the brain,present in each of the left and right hemispheres. Those regions in the left hemisphere area part of the “language areas” involved in human’s language processing, especially
responsible for the function of the “grammar center.” The homologues in the righthemisphere have the role of supporting the grammar center.
(Note 3) functional MRI (fMRI)
An imaging technology for measuring blood flow changes that accompany neuralactivations in the brain. The fMRI is broadly used from the 1990s as a method to wellobserve brain activations that change temporally, measured from outside of the brain
without causing any damage.

Contact information(Please ask the presenters about the research.)
Kuniyoshi L. Sakai, Professor
Department of Basic Science, Graduate School of Arts and Sciences, The University of Tokyo
3-8-1 Komaba, Meguro-Ku, Tokyo, 153-8902, Japan
Phone: +81-3-5454-6261
Email: sakai@sakai-lab.jp
Suzanne Flynn, Professor
Department of Linguistics and Philosophy, Massachusetts Institute of Technology
77 Massachusetts Avenue, 32‑D808, Cambridge, MA 02139, USA
Email: sflynn@mit.edu
Kazutake Hiraoka, General director
Institute for Language Experience, Experiment & Exchange (LEX Institute)
Aoyama H&A Bldg. 3F, 2-2-10 Shibuya, Shibuya-ku, Tokyo, 150-0002, Japan
Phone: +81-3-5467-7041 (main)
Email: kz-hiraoka@lexhippo.gr.jp

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