Syntactic structures in motion: investigating word order variations in verb-final (Korean) and verb-initial (Tongan) languages.

This study explored sentence processing in two typologically distinct languages: Korean, a verb-final language, and Tongan, a verb-initial language. The first experiment revealed that in Korean, sentences arranged in the scrambled OSV (Object, Subject, Verb) order were processed more slowly than those in the canonical SOV order, highlighting a scrambling effect. It also found that sentences with subject topicalization in the SOV order were processed as swiftly as those in the canonical form, whereas sentences with object topicalization in the OSV order were processed with speeds and accuracy comparable to scrambled sentences. However, since topicalization and scrambling in Korean use the same OSV order, independently distinguishing the effects of topicalization is challenging. In contrast, Tongan allows for a clear separation of word orders for topicalization and scrambling, facilitating an independent evaluation of topicalization effects. The second experiment, employing a maze task, confirmed that Tongan's canonical VSO order was processed more efficiently than the VOS scrambled order, thereby verifying a scrambling effect. The third experiment investigated the effects of both scrambling and topicalization in Tongan, finding that the canonical VSO order was processed most efficiently in terms of speed and accuracy, unlike the VOS scrambled and SVO topicalized orders. Notably, the OVS object-topicalized order was processed as efficiently as the VSO canonical order, while the SVO subject-topicalized order was slower than VSO but faster than VOS. By independently assessing the effects of topicalization apart from scrambling, this study demonstrates that both subject and object topicalization in Tongan facilitate sentence processing, contradicting the predictions based on movement-based anticipation.

Localizing Syntactic Composition with Left-Corner Recurrent Neural Network Grammars.

In computational neurolinguistics, it has been demonstrated that hierarchical models such as recurrent neural network grammars (RNNGs), which jointly generate word sequences and their syntactic structures via the syntactic composition, better explained human brain activity than sequential models such as long short-term memory networks (LSTMs). However, the vanilla RNNG has employed the top-down parsing strategy, which has been pointed out in the psycholinguistics literature as suboptimal especially for head-final/left-branching languages, and alternatively the left-corner parsing strategy has been proposed as the psychologically plausible parsing strategy. In this article, building on this line of inquiry, we investigate not only whether hierarchical models like RNNGs better explain human brain activity than sequential models like LSTMs, but also which parsing strategy is more neurobiologically plausible, by developing a novel fMRI corpus where participants read newspaper articles in a head-final/left-branching language, namely Japanese, through the naturalistic fMRI experiment. The results revealed that left-corner RNNGs outperformed both LSTMs and top-down RNNGs in the left inferior frontal and temporal-parietal regions, suggesting that there are certain brain regions that localize the syntactic composition with the left-corner parsing strategy.

Phonological encoding in Tongan: An experimental investigation.

This study is the first to report chronometric evidence on Tongan language production. It has been speculated that the mora plays an important role during Tongan phonological encoding. A mora follows the (C)V form, so /a/ and /ka/ (but not /k/) denote a mora in Tongan. Using a picture-word naming paradigm, Tongan native speakers named pictures containing superimposed non-word distractors. This task has been used before in Japanese, Korean, and Vietnamese to investigate the initially selected unit during phonological encoding (IPU). Compared with control distractors, both onset and mora overlapping distractors resulted in faster naming latencies. Several alternative explanations for the pattern of results-proficiency in English, knowledge of Latin script, and downstream effects-are discussed. However, we conclude that Tongan phonological encoding likely natively uses the phoneme, and not the mora, as the IPU.

Pupil Dilation Reflects Emotional Arousal Via Poetic Language.

We investigated pupillary responses to the world's shortest fixed verses, Japanese haiku as aesthetic poetry (AP) and senryu as comic poetry (CP), in comparison with non-poetry control stimuli (NP) comprised of slogans that had the same rhythm patterns. Native Japanese speakers without literary training listened to these stimuli while we recorded their pupil diameters. We found that participants' pupils were significantly dilated for CP compared to NP in an early time window. While AP also evoked larger dilations than NP, the latency for AP-related pupil dilation was relatively long. Thus, lay people experience quick and intense arousal in response to funny and humorous words, while aesthetic properties of words may also elicit intense but slower changes in listeners' arousal levels, presumably because they evoke more implicit and subtle emotional effects. This study is the first to provide evidence that poetic language elicits human pupillary dilation. A better understanding of the cognitive and neural substrates for the sensitive awareness of pleasures expressed via poetic language will provide insights for improving mental and physical health. Hence, pupillometry can act as a useful convenient measurement to delineate the sympathetic activation of emotional contexts via language.

Different Neural Responses for Unfinished Sentence as a Conventional Indirect Refusal Between Native and Non-native Speakers: An Event-Related Potential Study.

Refusal is considered a face-threatening act (FTA), since it contradicts the inviter's expectations. In the case of Japanese, native speakers (NS) are known to prefer to leave sentences unfinished for a conventional indirect refusal. Successful comprehension of this indirect refusal depends on whether the addressee is fully conventionalized to the preference for syntactic unfinishedness so that they can identify the true intention of the refusal. Then, non-native speakers (NNS) who are not fully accustomed to the convention may be confused by the indirect style. In the present study, we used event-related potentials (ERPs) of electroencephalography in an attempt to differentiate the neural substrates for perceiving unfinished sentences in a conventionalized indirect refusal as an FTA between NS and NNS, in terms of the unfinishedness and indirectness of the critical sentence. In addition, we examined the effects of individual differences in mentalization, or the theory of mind, which refers to the ability to infer the mental states of others. We found several different ERP effects for these refusals between NS and NNS. NNS induced stronger P600 effects for the unfinishedness of the refusal sentences, suggesting their perceived syntactic anomaly. This was not evoked in NS. NNS also revealed the effects of N400 and P300 for the indirectness of refusal sentences, which can be interpreted as their increased processing load for pragmatic processing in the inexperienced contextual flow. We further found that the NNS's individual mentalizing ability correlates with the effect of N400 mentioned above, indicating that lower mentalizers evoke higher N400 for indirect refusal. NS, on the contrary, did not yield these effects reflecting the increased pragmatic processing load. Instead, they evoked earlier ERPs of early posterior negativity (EPN) and P200, both of which are known as indices of emotional processing, for finished sentences of refusal than for unfinished ones. We interpreted these effects as a NS's dispreference for finished sentences to realize an FTA, given that unfinished sentences are considered more polite and more conventionalized in Japanese social encounters. Overall, these findings provide evidence that a syntactic anomaly inherent in a cultural convention as well as individual mentalizing ability plays an important role in understanding an indirect speech act of face-threatening refusal.

The Effect of Emotional State on the Processing of Morphosyntactic and Semantic Reversal Anomalies in Japanese: Evidence from Event-Related Brain Potentials.

The present study examined the locus responsible for the effect of emotional state on sentence processing in healthy native speakers of Japanese, using event-related brain potentials. The participants were induced into a happy, neutral, or sad mood and then subjected to electroencephalogram recording during which emotionally neutral sentences, including grammatical sentences (e.g. window-NOM close vi, 'The window closes.'), morphosyntactically-violated sentences (e.g. window-ACC close vi, Lit. 'Close the window.'), and semantically-reversed sentences (e.g. window-NOM close vt, 'The window closes pro.') were presented. The results of the ERP experiment demonstrated that while the P600 effect elicited by morphosyntactic violation was not modulated by mood, the P600 effect elicited by semantic reversal anomaly was observed only in participants previously induced into a happy mood. The LAN and N400 were not sensitive to the participants' transient emotional state. These results suggest intact memory access and impaired integration of syntactic and semantic information in individuals in a sad mood.

Dissociating Effects of Scrambling and Topicalization within the Left Frontal and Temporal Language Areas: An fMRI Study in Kaqchikel Maya.

Some natural languages grammatically allow different types of changing word orders, such as object scrambling and topicalization. Scrambling and topicalization are more related to syntax and semantics/phonology, respectively. Here we hypothesized that scrambling should activate the left frontal regions, while topicalization would affect the bilateral temporal regions. To examine such distinct effects in our functional magnetic resonance imaging study, we targeted the Kaqchikel Maya language, a Mayan language spoken in Guatemala. In Kaqchikel, the syntactically canonical word order is verb-object-subject (VOS), but at least three non-canonical word orders (i.e., SVO, VSO, and OVS) are also grammatically allowed. We used a sentence-picture matching task, in which the participants listened to a short Kaqchikel sentence and judged whether a picture matched the meaning of the sentence. The advantage of applying this experimental paradigm to an understudied language such as Kaqchikel is that it will allow us to validate the universality of linguistic computation in the brain. We found that the conditions with scrambled sentences [+scrambling] elicited significant activation in the left inferior frontal gyrus and lateral premotor cortex, both of which have been proposed as grammar centers, indicating the effects of syntactic loads. In contrast, the conditions without topicalization [-topicalization] resulted in significant activation in bilateral Heschl's gyrus and superior temporal gyrus, demonstrating that the syntactic and phonological processes were clearly dissociated within the language areas. Moreover, the pre-supplementary motor area and left superior/middle temporal gyri were activated under relatively demanding conditions, suggesting their supportive roles in syntactic or semantic processing. To exclude any semantic/phonological effects of the object-subject word orders, we performed direct comparisons while making the factor of topicalization constant, and observed localized activations in the left inferior frontal gyrus and lateral premotor cortex. These results establish that the types of scrambling and topicalization have different impacts on the specified language areas. These findings further indicate that the functional roles of these left frontal and temporal regions involve linguistic aspects themselves, namely syntax versus semantics/phonology, rather than output/input aspects of speech processing.

Social Interaction Affects Neural Outcomes of Sign Language Learning As a Foreign Language in Adults.

Children naturally acquire a language in social contexts where they interact with their caregivers. Indeed, research shows that social interaction facilitates lexical and phonological development at the early stages of child language acquisition. It is not clear, however, whether the relationship between social interaction and learning applies to adult second language acquisition of syntactic rules. Does learning second language syntactic rules through social interactions with a native speaker or without such interactions impact behavior and the brain? The current study aims to answer this question. Adult Japanese participants learned a new foreign language, Japanese sign language (JSL), either through a native deaf signer or via DVDs. Neural correlates of acquiring new linguistic knowledge were investigated using functional magnetic resonance imaging (fMRI). The participants in each group were indistinguishable in terms of their behavioral data after the instruction. The fMRI data, however, revealed significant differences in the neural activities between two groups. Significant activations in the left inferior frontal gyrus (IFG) were found for the participants who learned JSL through interactions with the native signer. In contrast, no cortical activation change in the left IFG was found for the group who experienced the same visual input for the same duration via the DVD presentation. Given that the left IFG is involved in the syntactic processing of language, spoken or signed, learning through social interactions resulted in an fMRI signature typical of native speakers: activation of the left IFG. Thus, broadly speaking, availability of communicative interaction is necessary for second language acquisition and this results in observed changes in the brain.

Interaction Between Syntactic Structure and Information Structure in the Processing of a Head-Final Language.

The effects of syntactic and information structures on sentence processing load were investigated using two reading comprehension experiments in Japanese, a head-final SOV language. In the first experiment, we discovered the main effects of syntactic and information structures, as well as their interaction, showing that interaction of these two factors is not restricted to head-initial languages. The second experiment revealed that the interaction between syntactic structure and information structure occurs at the second NP (O of SOV and S of OSV), which, crucially, is a pre-head position, suggesting the incremental nature of the processing of both syntactic structure and information structure in head-final languages.

Greater Left Inferior Frontal Activation for SVO than VOS during Sentence Comprehension in Kaqchikel.

Cortical activations during the processing of Kaqchikel transitive sentences with canonical and non-canonical word orders were investigated using functional magnetic resonance imaging. Kaqchikel is an endangered Mayan language spoken in Guatemala. The word order in this language is relatively flexible. We observed higher cortical activations in the left inferior frontal gyrus for sentences with the subject-verb-object (SVO) word order, as compared to sentences with the verb-object-subject (VOS) word order, suggesting that Kaqchikel sentences are easier to process when they have the VOS order than when they have the SVO order. This supports the traditional analysis of Mayan word order: the syntactically simplest word order of transitive sentences in Mayan languages, including Kaqchikel, is VOS. More importantly, the results revealed that the subject-before-object word order preference in sentence comprehension, previously observed in other languages, might not reflect a universal aspect of human languages. Rather, processing preference may be language-specific to some extent, reflecting syntactic differences in individual languages.

The Processing Cost of Scrambling and Topicalization in Japanese.

This article presents two reading comprehension experiments, using the sentence correctness decision task, that explore the causes of processing cost of Japanese sentences with SNOMOACCV, STOPOACCV, OACCSNOMV, and OTOPSNOMV word orders. The first experiment was conducted in order to see if either syntax or frequency plays a significant role in the processing of these sentences. The results of the first experiment have shown that both the structure-building process and frequency directly affect processing load. We observed that there was no difference in processing cost between SNOMOACCV and STOPOACCV, both of which are easier to process than OACCSNOMV, which is in turn easier to process than OTOPSNOMV: SNOMOACCV = STOPOACCV < OACCSNOMV < OTOPSNOMV. This result is the mixture of the two positions. Specifically, the structure building cost of STOPOACCV was neutralized by its high frequency. The aim of the second experiment was to investigate the interaction between syntactic structure, frequency, and information structure. The results showed that the processing cost of OACCSNOMV was facilitated by given-new ordering, but SNOMOACCV, STOPOACCV, and OTOPSNOMV were not. Thus, we can conclude that information structure also influences processing cost. In addition, the distribution of informational effects can be accounted for by Kuno's (1987, p. 212) Markedness Principle for Discourse Rule Violations: SNOMOACCV and STOPOACCV are unmarked/canonical options, and as such are not penalized even when they violate given-new ordering, OACCSNOMV is penalized when it does not maintain given-new ordering because it is a marked/non-canonical option, and OTOPSNOMV is penalized even when it obeys given-new ordering possibly because more specific contexts are needed. Another reason for the increased processing cost of OTOPSNOMV is a garden path effect; upon encountering OTOP of OTOPSNOMV, the parser preferentially (mis)interpreted it as STOP due to a subject-before-object preference. The revision of the interpretation may be the cause of the high processing cost observed in OTOPSNOMV.

Dialectal differences in hemispheric specialization for Japanese lexical pitch accent.

Language experience can alter perceptual abilities and the neural specialization for phonological contrasts. Here we investigated whether dialectal differences in the lexical use of pitch information lead to differences in functional lateralization for pitch processing. We measured cortical hemodynamic responses to pitch pattern changes in native speakers of Standard (Tokyo) Japanese, which has a lexical pitch accent system, and native speakers of 'accentless' dialects, which do not have any lexical tonal phenomena. While the Standard Japanese speakers showed left-dominant responses in temporal regions to pitch pattern changes within words, the accentless dialects speakers did not show such left-dominance. Pitch pattern changes within harmonic-complex tones also elicited different brain activation patterns between the two groups. These results indicate that the neural processing of pitch information differs depending on the listener's native dialect, and that listeners' linguistic experiences may further affect the processing of pitch changes even for non-linguistic sounds.

Left inferior frontal activations depending on the canonicity determined by the argument structures of ditransitive sentences: an MEG study.

To elucidate the relationships between syntactic and semantic processes, one interesting question is how syntactic structures are constructed by the argument structure of a verb, where each argument corresponds to a semantic role of each noun phrase (NP). Here we examined the effects of possessivity [sentences with or without a possessor] and canonicity [canonical or noncanonical word orders] using Japanese ditransitive sentences. During a syntactic decision task, the syntactic structure of each sentence would be constructed in an incremental manner based on the predicted argument structure of the ditransitive verb in a verb-final construction. Using magnetoencephalography, we found a significant canonicity effect on the current density in the left inferior frontal gyrus (IFG) at 530-550 ms after the verb onset. This effect was selective to canonical sentences, and significant even when the precedent NP was physically identical. We suggest that the predictive effects associated with syntactic processing became larger for canonical sentences, where the NPs and verb were merged with a minimum structural distance, leading to the left IFG activations. For monotransitive and intransitive verbs, in which structural computation of the sentences was simpler than that of ditransitive sentences, we observed a significant effect selective to noncanonical sentences in the temporoparietal regions during 480-670 ms. This effect probably reflects difficulty in semantic processing of noncanonical sentences. These results demonstrate that the left IFG plays a predictive role in syntactic processing, which depends on the canonicity determined by argument structures, whereas other temporoparietal regions would subserve more semantic aspects of sentence processing.

Effect of second language exposure on brain activity for language processing among preschoolers.

We investigated brain activity in 3-5-year-old preschoolers as they listened to connected speech stimuli in Japanese (first language), English (second language), and Chinese (a rarely exposed, foreign language) using near-infrared spectroscopy. Unlike the younger preschoolers who had been exposed to English for almost 1 year, brain activity in the bilateral frontal regions of the older preschoolers who had been exposed to English for almost 2 years was higher for Japanese and English speech stimuli than for Chinese. This tendency seemed to be similar to that observed in adults who had learned English for some years. These results indicate that exposure to a second language affects brain activity to language stimuli among preschoolers.

Second-language instinct and instruction effects: nature and nurture in second-language acquisition.

Adults seem to have greater difficulties than children in acquiring a second language (L2) because of the alleged "window of opportunity" around puberty. Postpuberty Japanese participants learned a new English rule with simplex sentences during one month of instruction, and then they were tested on "uninstructed complex sentences" as well as "instructed simplex sentences." The behavioral data show that they can acquire more knowledge than is instructed, suggesting the interweaving of nature (universal principles of grammar, UG) and nurture (instruction) in L2 acquisition. The comparison in the "uninstructed complex sentences" between post-instruction and pre-instruction using functional magnetic resonance imaging reveals a significant activation in Broca's area. Thus, this study provides new insight into Broca's area, where nature and nurture cooperate to produce L2 learners' rich linguistic knowledge. It also shows neural plasticity of adult L2 acquisition, arguing against a critical period hypothesis, at least in the domain of UG.

Effects of non-native language exposure on the semantic processing of native language in preschool children.

We investigated the effects of non-native language (English) exposure on event-related potentials (ERPs) in first- and second-year (four- and five-year-old) preschool Japanese native speakers while they listened to semantically congruent and incongruent Japanese sentences. The children were divided into a non-native language exposed group (exposed group) and a group without such experiences (control group) on the basis of their exposure to non-native language. We compared the ERPs recorded from the two groups in each of the two preschool years. N400 was observed both in the first- and second-year preschoolers. Differences owing to exposure to non-native language appeared in the second-year preschoolers but not in the first-year preschoolers. In the second-year preschoolers, the N400 onset in the exposed group was shorter than that in the control group, but there was no difference in the N400 offset between the exposed and control groups. Furthermore, the scalp distribution of the N400 in the exposed group was broader than that in the control group. These results indicate that the time course and scalp distribution of semantic processing for native language sentences in young children fluctuated depending on exposure to non-native language.

Priority information used for the processing of Japanese sentences: thematic roles, case particles or grammatical functions?

The present study investigated scrambling effects on the processing of Japanese sentences and priority information used among thematic roles, case particles and grammatical functions. Reaction times for correct sentence decisions were significantly prolonged for scrambled active sentences with transitive verbs in the first experiment and with ditransitive verbs in the second experiment. Errors were made with scrambled sentences more than canonical sentences in both experiments, which suggested that scrambling effects were apparent in active sentences. Passive sentences in the third experiment indicated that canonical order defined based on case particles, not thematic roles, was more quickly and accurately identified than scrambled order. Potential sentences in the fourth experiment and causative sentences in the fifth experiment indicated that the processing of scrambled sentences based on grammatical functions, but not on case particles, required longer reaction times and resulted in higher error rates than canonical sentences. Consequently, scrambling effects in the present study indicated that neither thematic roles nor case particles can provide fully-satisfactory information for canonical phrase order, and that only grammatical functions offer satisfactory information in all types of sentences.

Light-driven expulsion of the sterically hindering ligand L in tris-diimine ruthenium(II) complexes of the Ru(phen)2(L)2+ family: a pronounced ring effect.

Three new ruthenium(II) complexes have been prepared which contain two 1,10-phenanthroline units and a third sterically hindering chelate. In one case, the hindering ligand is a disubstituted 2,2'-bipyridine (bpy) attached to two very bulky manisyl groups. The two other systems are similar in terms of size of the hindering groups (anisyl substituents) located close to the central metal. The complexes investigated in the Present Report are aimed at providing building blocks of future light-driven molecular machines. The photochemical expulsion of the sterically hindering chelate has thus been studied by UV-vis spectroscopy and 1H NMR. Surprisingly, the manisyl-containing complex turned out to be photochemically inert, indicating that a too bulky group acts as a protecting function versus decomplexation rather than as a destabilizing group. For the two other systems, a pronounced ring effect was observed: whereas the acyclic systems undergo fast photochemical expulsion of the bipy-based ligand, in the cyclic complex, the bipy-incorporating ring is decoordinated about 5 times less efficiently than the acyclic ligand of the previous case. These observations on the strong dependence of the photochemical behavior of the ruthenium(II) complexes on their structural properties are corroborated by X-ray diffraction studies on the three compounds investigated.

trans-RuH(eta1-BH4)(binap)(1,2-diamine): a catalyst for asymmetric hydrogenation of simple ketones under base-free conditions.

Reaction of a chiral RuCl2(diphosphine)(1,2-diamine) complex and NaBH4 forms trans-RuH(eta1-BH4)(diphosphine)(1,2-diamine) quantitatively. The TolBINAP/DPEN Ru complex has been characterized by single crystal X-ray analysis as well as NMR and IR spectra. The new Ru complexes allow for asymmetric hydrogenation of simple ketones in 2-propanol without an additional strong base. Various base-sensitive ketones are convertible to chiral alcohols in a high enantiomeric purity with a substrate/catalyst ratio of up to 100 000 under mild conditions. Configurationally unstable 2-isopropyl- and 2-methoxycyclohexanone can be kinetically resolved with a high enantiomer discrimination. This procedure overcomes the drawback of an earlier method using RuCl2(diphosphine)(diamine) and an alkaline base, which sometimes causes undesired reactions such as ester exchange, epoxy-ring opening, beta-elimination, and polymerization of ketonic substrates.