Age of sign language acquisition has lifelong effect on syntactic preferences in sign language users.

Acquisition of natural language has been shown to fundamentally impact both one's ability to use the first language, and the ability to learn subsequent languages later in life. Sign languages offer a unique perspective on this issue, because Deaf signers receive access to signed input at varying ages. The majority acquires sign language in (early) childhood, but some learn sign language later - a situation that is drastically different from that of spoken language acquisition. To investigate the effect of age of sign language acquisition and its potential interplay with age in signers, we examined grammatical acceptability ratings and reaction time measures in a group of Deaf signers (age range: 28-58 years) with early (0-3 years) or later (4-7 years) acquisition of sign language in childhood. Behavioral responses to grammatical word order variations (subject-object-verb vs. object-subject-verb) were examined in sentences that included: 1) simple sentences, 2) topicalized sentences, and 3) sentences involving manual classifier constructions, uniquely characteristic of sign languages. Overall, older participants responded more slowly. Age of acquisition had subtle effects on acceptability ratings, whereby the direction of the effect depended on the specific linguistic structure.

Psycholinguistic mechanisms of classifier processing in sign language.

Nonsigners viewing sign language are sometimes able to guess the meaning of signs by relying on the overt connection between form and meaning, or iconicity (cf. Ortega, Özyürek, & Peeters, 2020; Strickland et al., 2015). One word class in sign languages that appears to be highly iconic is classifiers: verb-like signs that can refer to location change or handling. Classifier use and meaning are governed by linguistic rules, yet in comparison with lexical verb signs, classifiers are highly variable in their morpho-phonology (variety of potential handshapes and motion direction within the sign). These open-class linguistic items in sign languages prompt a question about the mechanisms of their processing: Are they part of a gestural-semiotic system (processed like the gestures of nonsigners), or are they processed as linguistic verbs? To examine the psychological mechanisms of classifier comprehension, we recorded the electroencephalogram (EEG) activity of signers who watched videos of signed sentences with classifiers. We manipulated the sentence word order of the stimuli (subject-object-verb [SOV] vs. object-subject-verb [OSV]), contrasting the two conditions, which, according to different processing hypotheses, should incur increased processing costs for OSV orders. As previously reported for lexical signs, we observed an N400 effect for OSV compared with SOV, reflecting increased cognitive load for linguistic processing. These findings support the hypothesis that classifiers are a linguistic part of speech in sign language, extending the current understanding of processing mechanisms at the interface of linguistic form and meaning. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Age of acquisition effects differ across linguistic domains in sign language: EEG evidence.

One of the key questions in the study of human language acquisition is the extent to which the development of neural processing networks for different components of language are modulated by exposure to linguistic stimuli. Sign languages offer a unique perspective on this issue, because prelingually Deaf children who receive access to complex linguistic input later in life provide a window into brain maturation in the absence of language, and subsequent neuroplasticity of neurolinguistic networks during late language learning. While the duration of sensitive periods of acquisition of linguistic subsystems (sound, vocabulary, and syntactic structure) is well established on the basis of L2 acquisition in spoken language, for sign languages, the relative timelines for development of neural processing networks for linguistic sub-domains are unknown. We examined neural responses of a group of Deaf signers who received access to signed input at varying ages to three linguistic phenomena at the levels of classifier signs, syntactic structure, and information structure. The amplitude of the N400 response to the marked word order condition negatively correlated with the age of acquisition for syntax and information structure, indicating increased cognitive load in these conditions. Additionally, the combination of behavioral and neural data suggested that late learners preferentially relied on classifiers over word order for meaning extraction. This suggests that late acquisition of sign language significantly increases cognitive load during analysis of syntax and information structure, but not word-level meaning.

Language Processing as a Precursor to Language Change: Evidence From Icelandic.

One of the main characteristics of human languages is that they are subject to fundamental changes over time. However, because of the long transitional periods involved, the internal dynamics of such changes are typically inaccessible. Here, we present a new approach to examining language change via its connection to language comprehension. By means of an EEG experiment on Icelandic, a prominent current example of a language in transition, we show that the neurophysiological responses of native speakers already reflect projected changes that are not yet apparent in their overt behavior. Neurocognitive measures thus offer a means of predicting, rather than only retracing, language change.

The Impact of Transitional Movements and Non-Manual Markings on the Disambiguation of Locally Ambiguous Argument Structures in Austrian Sign Language (ÖGS).

Previous studies of Austrian Sign Language (ÖGS) word-order variations have demonstrated the human processing system's tendency to interpret a sentence-initial (case-) ambiguous argument as the subject of the clause ("subject preference"). The electroencephalogram study motivating the current report revealed earlier reanalysis effects for object-subject compared to subject-object sentences, in particular, before the start of the movement of the agreement marking sign. The effects were bound to time points prior to when both arguments were referenced in space and/or the transitional hand movement prior to producing the disambiguating sign. Due to the temporal proximity of these time points, it was not clear which visual cues led to disambiguation; that is, whether non-manual markings (body/shoulder/head shift towards the subject position) or the transitional hand movement resolved ambiguity. The present gating study further supports that disambiguation in ÖGS is triggered by cues occurring before the movement of the disambiguating sign. Further, the present study also confirms the presence of the subject preference in ÖGS, showing again that signers and speakers draw on similar strategies during language processing independent of language modality. Although the ultimate role of the visual cues leading to disambiguation (i.e., non-manual markings and transitional movements) requires further investigation, the present study shows that they contribute crucial information about argument structure during online processing. This finding provides strong support for granting these cues some degree of linguistic status (at least in ÖGS).

Subject preference emerges as cross-modal strategy for linguistic processing.

Research on spoken languages has identified a "subject preference" processing strategy for tackling input that is syntactically ambiguous as to whether a sentence-initial NP is a subject or object. The present study documents that the "subject preference" strategy is also seen in the processing of a sign language, supporting the hypothesis that the "subject"-first strategy is universal and not dependent on the language modality (spoken vs. signed). Deaf signers of Austrian Sign Language (ÖGS) were shown videos of locally ambiguous signed sentences in SOV and OSV word orders. Electroencephalogram (EEG) data indicated higher cognitive load in response to OSV stimuli (i.e. a negativity for OSV compared to SOV), indicative of syntactic reanalysis cost. A finding that is specific to the visual modality is that the ERP (event-related potential) effect reflecting linguistic reanalysis occurred earlier than might have been expected, that is, before the time point when the path movement of the disambiguating sign was visible. We suggest that in the visual modality, transitional movement of the articulators prior to the disambiguating verb position or co-occurring non-manual (face/body) markings were used in resolving the local ambiguity in ÖGS. Thus, whereas the processing strategy of "subject preference" is cross-modal at the linguistic level, the cues that enable the processor to apply that strategy differ in signing as compared to speech.

The costs of being certain: Brain potential evidence for linguistic preactivation in sentence processing.

Prediction in sentence comprehension is often investigated by measuring the amplitude of the N400 ERP component to words that are more or less predictable from their preceding context. The N400-linked to the activation of word-associated semantic information-is reduced for words that are predictable, indicating that preactivation can lead to facilitated processing. We addressed the question whether there is measurable neural activity related to the preactivation of linguistic information before input confirms or disconfirms this prediction. We therefore measured ERPs not only to moderately to highly predictable target words, but also to preceding adverbs. Based on two separate cloze pretests, we quantified the impact of the adverb upon the predictability of the subsequent target word. Using linear mixed-effects analyses, we could show that the N400 amplitude at the target word was inversely related to target cloze value, thus replicating the finding that prediction has a facilitative effect on semantic processing. Crucially, the N400 amplitude at the pretarget adverb was modulated by adverb impact: When adverbs increased the predictability of the following word, the N400 was more negative going. We argue that this effect is related to the preactivation of linguistic information. Our findings indicate that the specification of predictions can lead to additional processes before these predictions are confirmed or disconfirmed and that activation of word-associated information through prediction is highly comparable to activation through actual input.

Semantic prediction in language comprehension: evidence from brain potentials.

Do people predict specific word-forms during language comprehension? In an Event-Related Potential (ERP) study participants read German sentences with predictable (The goalkeeper claims that the slick ball was easy to CATCH.) and unpredictable (The kids boasted that the young horse was easy to SADDLE.) verbs. Verbs were either consistent with the expected word-form (catch/saddle) or inconsistent and therefore led to ungrammaticality (*catches/*saddles). ERPs within the N400 time-window were modulated by predictability but not by the surface-form of the verbs, suggesting that no exact word-forms were predicted. Based on our results we will argue that predictions included semantic rather than form-information. Furthermore, ungrammatical verbs led to a strong P600, probably due to task-saliency whereas correct unpredictable verbs elicited an anterior post-N400 positivity. Because the contexts were moderately constraining, this might reflect discourse revision processes rather than inhibition of a predicted word.

Marking the counterfactual: ERP evidence for pragmatic processing of German subjunctives.

Counterfactual conditionals are frequently used in language to express potentially valid reasoning from factually false suppositions. Counterfactuals provide two pieces of information: their literal meaning expresses a suppositional dependency between an antecedent (If the dice had been rigged…) and a consequent (… then the game would have been unfair). Their second, backgrounded meaning refers to the opposite state of affairs and suggests that, in fact, the dice were not rigged and the game was fair. Counterfactual antecedents are particularly intriguing because they set up a counterfactual world which is known to be false, but which is nevertheless kept to when evaluating the conditional's consequent. In the last years several event-related potential (ERP) studies have targeted the processing of counterfactual consequents, yet counterfactual antecedents have remained unstudied. We present an EEG/ERP investigation which employed German conditionals to compare subjunctive mood (which marks counterfactuality) with indicative mood at the critical point of mood disambiguation via auxiliary introduction in the conditional's antecedent. Conditional sentences were presented visually one word at a time. Participants completed an acceptability judgment and probe detection task which was not related to the critical manipulation of linguistic mood. ERPs at the point of mood disambiguation in the antecedent were compared between indicative and subjunctive. Our main finding is a transient negative deflection in frontal regions for subjunctive compared to indicative mood in a time-window of 450-600 ms. We discuss this novel finding in respect to working memory requirements for rule application and increased referential processing demands for the representation of counterfactuals' dual meaning. Our result suggests that the counterfactually implied dual meaning is processed without any delay at the earliest point where counterfactuality is marked by subjunctive mood.

Oscillatory brain activity in vegetative and minimally conscious state during a sentence comprehension task.

Patients with altered states of consciousness continue to constitute a major challenge in terms of clinical assessment, treatment and daily management. Furthermore, the exploration of brain function in severely brain-damaged patients represents a unique lesional approach to the scientific study of consciousness. Electroencephalography is one means of identifying covert behaviour in the absence of motor activity in these critically ill patients. Here we focus on a language processing task which assesses whether vegetative (n=10) and minimally conscious state patients (n=4) (vs control subjects, n=14) understand semantic information on a sentence level ("The opposite of black is... white/yellow/nice"). Results indicate that only MCS but not VS patients show differential processing of unrelated ("nice") and antonym ("white") words in the form of parietal alpha (10-12Hz) event-related synchronization and desynchronization (ERS/ERD), respectively. Controls show a more typical pattern, characterized by alpha ERD in response to unrelated words and alpha ERS in response to antonyms.

Think globally: cross-linguistic variation in electrophysiological activity during sentence comprehension.

This paper demonstrates systematic cross-linguistic differences in the electrophysiological correlates of conflicts between form and meaning ("semantic reversal anomalies"). These engender P600 effects in English and Dutch (e.g. Kolk et al., 2003; Kuperberg et al., 2003), but a biphasic N400 - late positivity pattern in German (Schlesewsky and Bornkessel-Schlesewsky, 2009), and monophasic N400 effects in Turkish (Experiment 1) and Mandarin Chinese (Experiment 2). Experiment 3 revealed that, in Icelandic, semantic reversal anomalies show the English pattern with verbs requiring a position-based identification of argument roles, but the German pattern with verbs requiring a case-based identification of argument roles. The overall pattern of results reveals two separate dimensions of cross-linguistic variation: (i) the presence vs. absence of an N400, which we attribute to cross-linguistic differences with regard to the sequence-dependence of the form-to-meaning mapping and (ii) the presence vs. absence of a late positivity, which we interpret as an instance of a categorisation-related late P300, and which is observable when the language under consideration allows for a binary well-formedness categorisation of reversal anomalies. We conclude that, rather than reflecting linguistic domains such as syntax and semantics, the late positivity vs. N400 distinction is better understood in terms of the strategies that serve to optimise the form-to-meaning mapping in a given language.

The N400 as a correlate of interpretively relevant linguistic rules: evidence from Hindi.

Classical views on the electrophysiology of language assume that different event-related potential (ERP) components index distinct linguistic subdomains. Hence, left-anterior negativities are often viewed as correlates of rule-based linguistic knowledge, whereas centro-parietal negativities (N400s) are taken to reflect (non-rule-based) semantic memory or aspects of lexical-semantic predictability. The present ERP study of case marking in Hindi challenges this clear-cut dichotomy. Though determined by a grammatical rule, the choice of subject case in Hindi is also interpretively relevant as it constrains the range of possible interpretations of the subject. For incorrect subject cases, we observed an N400, which was followed by a late positivity under certain circumstances. This finding suggests that violations of rule-based knowledge may engender an N400 when the rule is interpretively relevant.

To predict or not to predict: influences of task and strategy on the processing of semantic relations.

We report a series of event-related potential experiments designed to dissociate the functionally distinct processes involved in the comprehension of highly restricted lexical-semantic relations (antonyms). We sought to differentiate between influences of semantic relatedness (which are independent of the experimental setting) and processes related to predictability (which differ as a function of the experimental environment). To this end, we conducted three ERP studies contrasting the processing of antonym relations (black-white) with that of related (black-yellow) and unrelated (black-nice) word pairs. Whereas the lexical-semantic manipulation was kept constant across experiments, the experimental environment and the task demands varied: Experiment 1 presented the word pairs in a sentence context of the form The opposite of X is Y and used a sensicality judgment. Experiment 2 used a word pair presentation mode and a lexical decision task. Experiment 3 also examined word pairs, but with an antonymy judgment task. All three experiments revealed a graded N400 response (unrelated > related > antonyms), thus supporting the assumption that semantic associations are processed automatically. In addition, the experiments revealed that, in highly constrained task environments, the N400 gradation occurs simultaneously with a P300 effect for the antonym condition, thus leading to the superficial impression of an extremely "reduced" N400 for antonym pairs. Comparisons across experiments and participant groups revealed that the P300 effect is not only a function of stimulus constraints (i.e., sentence context) and experimental task, but that it is also crucially influenced by individual processing strategies used to achieve successful task performance.

Differential effects of saliency: an event-related brain potential study.

We present event-related brain potential evidence from language comprehension that the N400-modulation during noun-phrase integration is a function of the type of referential dependency that is established (identity versus inference) and the saliency (in the following understood as the sum of factors that influence the degree of accessibility of an entity in the mental model) of the information unit that serves as an anchor for the dependency. Identity relations revealed a reduced N400 compared to inferential relations, confirming previous findings. More importantly, the investigation provides novel findings concerning the effect of saliency on noun-phrase integration: identity relations did not reveal a difference in the N400 as a function of the saliency manipulation. In contrast, inferential relations showed a more pronounced N400 with less salient anchors compared to inferential relations that involved a highly salient anchor. Moreover, no difference in N400-amplitude obtained between less salient inference-based entities and new information units. These data suggest that inferential processes are blocked in the absence of a highly accessible anchor. The findings generally indicate that the language system is not only sensitive to the kind of dependency that is established, but also to the saliency of the entity that serves as anchor for the dependency. The data further demonstrate that the processing system is responsive to semantic- and discourse-level information during the interpretation of noun-phrases.

When case meets agreement: event-related potential effects for morphology-based conflict resolution in human language comprehension.

We present event-related potential evidence from language comprehension that processing conflicts arising from the same linguistic domain and appearing within the same time range do not interact when they draw upon distinct underlying neural populations. Thus, a combined violation of two morphosyntactic information types, number-agreement and case, engendered a LAN/N400-P600 pattern, while the corresponding single violations are associated with LAN-P600 and N400-P600 responses, respectively. The absence of an interaction between the two negativities indicates that neuronal resource sharing does not result from a similarity of function, but rather requires an overlap of the underlying neuronal populations.

Fractionating language comprehension via frequency characteristics of the human EEG.

We present a new analysis technique for EEG research on language comprehension, which dissociates superficially indistinguishable event-related potential (ERP) components. A frequency-based analysis differentiated between two apparently identical but functionally distinct N400 effects in terms of activity in separable frequency bands, and whether the activity stemmed from increased power or phase locking. Whereas linguistic problem detection is associated with theta band activity (approximately 3.5-7.5 Hz), conflict resolution correlates with activity in the delta band (1-3 Hz). The data further differentiate between the neuronal processing mechanisms involved in different types of conflict resolution on the basis of frequency characteristics (power vs phase locking).