Non-native Signers Research Articles

Use of a factor analysis to assess biomechanical factors of American Sign Language in native and non-native signers

Prior studies suggest that native (born to at least one deaf or signing parent) and non-native signers have different musculoskeletal health outcomes from signing, but the individual and combined biomechanical factors driving these differences are not fully understood. Such group differences in signing may be explained by the five biomechanical factors of American Sign Language that have been previously identified: ballistic signing, hand and wrist deviations, work envelope, muscle tension, and “micro” rests. Prior work used motion capture and surface electromyography to collect joint kinematics and muscle activations, respectively, from ten native and thirteen non-native signers as they signed for 7.5 min. Each factor was individually compared between groups. A factor analysis was used to determine the relative contributions of each biomechanical factor between signing groups. No significant differences were found between groups for ballistic signing, hand and wrist deviations, work envelope volume, excursions from recommended work envelope, muscle tension, or “micro” rests. Factor analysis revealed that “micro” rests had the strongest contribution for both groups, while hand and wrist deviations had the weakest contribution. Muscle tension and work envelope had stronger contributions for native compared to non-native signers, while ballistic signing had a stronger contribution for non-native compared to native signers. Using a factor analysis enabled discernment of relative contributions of biomechanical variables across native and non-native signers that could not be detected through isolated analysis of individual measures. Differences in the contributions of these factors may help explain the differences in signing across native and non-native signers.

Assessing Lexical and Syntactic Comprehension in Deaf Signing Adults.

Among the existing sign language assessment tools, only a small number can be used in clinical settings. This contribution aims at presenting three comprehension assessment tests (two lexical and one syntactic) that offer a solid basis to build tools to assess language impairments in deaf signing adults. We provide the material and guidelines, based on psychometric analyses of the items, to make these tests suitable for clinical assessment. They are available for French Sign Language and Italian Sign Language. So far, the three tests were administered to three groups of deaf participants based on age of exposure (AoE) to sign language: native (AoE from birth), early (AoE = from 1 to 5years), and late (AoE = from 6 to 15years) signers. The results showed that the three tests are easy for the typical deaf signing population, and therefore, they can be adapted into tests that assess a deaf signing population with language impairments. Moreover, the results of the syntactic test reveal a categorial difference between native and non-native signers and therefore show the need for baselines that mirror the effect of AoE to sign language when assessing language competence, in particular in clinical assessment.

On the nature of role shift

Attitude role shift is a sign language strategy to report someone else’s utterance or thought. It has been analyzed either as a kind of demonstration or, alternatively, as a complex construction involving subordination plus a context-shifting operator. The present work reports the results of a sentence-to-picture matching task developed in three different sign languages (Italian Sign Language, French Sign Language and Catalan Sign Language) with the aim of providing experimental evidence about the nature of role shift. The task assessed the comprehension of indexical first-person pronouns in various syntactic contexts with and without role shift. We showed that constructions with role shift, which require context-shifting for the first-person pronoun, are never easier to comprehend than constructions without role shift that do not require context-shifting. In some cases, they are even more difficult. Additionally, we show that, in Italian Sign Language only, sentences in which the role shifted first-person pronoun is in object position are more difficult than sentences in which it is in subject position. We argue that this can be interpreted as an intervention effect and that this is an argument in favor of positing a context-shifting operator in the periphery of the role shift clause. Considering that the population of adult Deaf signers includes, besides native signers, a majority of individuals with a more or less severe delayed first language exposure, the second goal of this paper is to study the effects of age of exposure on comprehension of sentences with role shift. In the three languages under investigation, we found that native signers generally outperformed non-native signers in sentences with role shift and in subordinate clauses without role shift. This confirms that delayed language exposure has a lasting impact on adults’ comprehension of subordinate clauses of various degrees of complexity.

Upper extremity biomechanics in native and non-native signers.

Individuals fluent in sign language (signers) born to non-signing, non-deaf parents (non-natives) may have a greater injury risk than signers born to signing, deaf parents (natives). A comprehensive analysis of movement while signing in natives and non-natives has not been completed and could provide insight into the greater injury prevalence of non-natives. The objective of this study was to determine differences in upper extremity biomechanics between non-natives and natives. Strength, 'micro' rests, muscle activation, ballistic signing, joint angle, and work envelope were captured across groups. Non-natives had fewer rests (p = 0.002) and greater activation (p = 0.008) in non-dominant upper trapezius. For ballistic signing, natives had greater anterior-posterior jerk (p = 0.033) and for joint angle, natives demonstrated greater wrist flexion-extension range of motion (p = 0.040). Natives also demonstrated greater maximum medial-lateral (p = 0.015), and greater minimum medial-lateral (p = 0.019) and superior-inferior (p = 0.027) positions. We observed that natives presented with more rests and less activation, but greater ballistic tendencies, joint angle, and envelope compared to non-natives. Additional work should explore potential links between these outcomes and injury risk in signers.

Age of exposure and subject/object asymmetries when wh-movement goes rightward

Abstract We report an experiment addressing the comprehension of LIS interrogatives in three adult populations with different times of exposure to sign language: native signers, early signers, and late signers. We investigate whether delayed exposure to language affects comprehension of interrogatives and whether there is an advantage for subject dependencies over object dependencies, as systematically reported for spoken languages. The answer to the first question is positive: there is evidence that natives outperform non-native signers, confirming permanent effects of delayed exposure to sign language even decades after childhood. However, the performance in subject interrogatives was lower than in object interrogatives in all groups of participants. We discuss several possible reasons for this unexpected finding.

Asymmetries in relative clause comprehension in three European sign languages

Relativization is a robust subordinating type across languages, displaying important typological variability concerning the position of the nominal head that the relative clause modifies, and sign languages are no exception. It has been widely assumed since Keenan & Comrie (1977) that the subject position is more accessible to relativization than object and oblique positions. The main aim of this paper is to investigate the extension of this famous generalization both across modalities (sign as opposed to spoken languages) and across relativization typologies (internally as opposed to externally headed relatives), and to verify how it interacts with age of first language exposure. We here report the results of a sentence-to-picture matching task assessing the comprehension of subject and object relative clauses (RCs) in three sign languages: French Sign Language (LSF), Catalan Sign Language (LSC), and Italian Sign Language (LIS). The results are that object RCs are never easier to comprehend than subject RCs. Remarkably, this is independent from the type of relative clause (internally or externally headed). As for the impact of age of exposure, we found that native signers outperform non-native signers and that a delay in language exposure emphasizes the subject/object asymmetry. Our results introduce a new potential diagnostic for LF movement: the existence of a Subject Advantage in comprehension can be used as a reliable and measurable cue for the existence of long-distance dependencies, including covert ones.

Language experience in LSF development: Behavioral evidence from a sentence repetition task.

In psycholinguistics and clinical linguistics, the Sentence Repetition Task (SRT) is known to be a valuable tool to screen general language abilities in both spoken and signed languages. This task enables users to reliably and quickly assess linguistic abilities at different levels of linguistic analysis such as phonology, morphology, lexicon, and syntax. To evaluate sign language proficiency in deaf children using French Sign Language (LSF), we designed a new SRT comprising 20 LSF sentences. The task was administered to a cohort of 62 children- 34 native signers (6;09-12 years) and 28 non-native signers (6;08-12;08 years)-in order to study their general linguistic development as a function of age of sign language acquisition (AOA) and chronological age (CA). Previously, a group of 10 adult native signers was also evaluated with this task. As expected, our results showed a significant effect of AOA, indicating that the native signers repeated more signs and were more accurate than non-native signers. A similar pattern of results was found for CA. Furthermore, native signers made fewer phonological errors (i.e., handshape, movement, and location) than non-native signers. Finally, as shown in previous sign language studies, handshape and movement proved to be the most difficult parameters to master regardless of AOA and CA. Taken together, our findings support the assumption that AOA is a crucial factor in the development of phonological skills regardless of language modality (spoken vs. signed). This study thus constitutes a first step toward a theoretical description of the developmental trajectory in LSF, a hitherto understudied language.

The Modified Strain Index: A Composite Measure of Injury Risk for Signers

Up to 81% of individuals who are fluent in sign language (signers) report pain. Non-native signers (with non-signing, non-deaf parents) report greater pain than natives (≥1 signing, deaf parent). The goal of this study was to develop a composite measure of injury risk (the modified Strain Index for signers) based on previously identified biomechanics unique to signers and examine scores across sub-groups of natives and non-natives. Non-natives were hypothesized to have greater pain and higher composite scores than natives. Ten natives and 15 non-natives used a numeric scale to rate pain while signing. Measures included ‘micro’ rests, muscle activation, ballistic signing, non-neutral joint angle, and work envelope. Descriptive statistics were used to create categorical ratings and backward elimination multiple linear regression to establish rank order of the biomechanical tasks. Participant performance was rated, and the product of the multipliers across tasks created a score. Pain intensity was associated with the composite score (r = 0.46; p = 0.02), however there was no difference between natives (score = 13.39 ± 3.1) and non-natives (score = 19.55 ± 4.7; p = 0.34). This work presents an approach to incorporate multiple biomechanical factors into a single, composite measure unique to signers, however further evidence-based adjustments are needed to enhance its robustness.

Sociolinguistic Typology and Sign Languages.

This paper examines the possible relationship between proposed social determinants of morphological ‘complexity’ and how this contributes to linguistic diversity, specifically via the typological nature of the sign languages of deaf communities. We sketch how the notion of morphological complexity, as defined by Trudgill (2011), applies to sign languages. Using these criteria, sign languages appear to be languages with low to moderate levels of morphological complexity. This may partly reflect the influence of key social characteristics of communities on the typological nature of languages. Although many deaf communities are relatively small and may involve dense social networks (both social characteristics that Trudgill claimed may lend themselves to morphological ‘complexification’), the picture is complicated by the highly variable nature of the sign language acquisition for most deaf people, and the ongoing contact between native signers, hearing non-native signers, and those deaf individuals who only acquire sign languages in later childhood and early adulthood. These are all factors that may work against the emergence of morphological complexification. The relationship between linguistic typology and these key social factors may lead to a better understanding of the nature of sign language grammar. This perspective stands in contrast to other work where sign languages are sometimes presented as having complex morphology despite being young languages (e.g., Aronoff et al., 2005); in some descriptions, the social determinants of morphological complexity have not received much attention, nor has the notion of complexity itself been specifically explored.

An Eye Tracking Study on the Perception and Comprehension of Unimodal and Bimodal Linguistic Inputs by Deaf Adolescents.

An eye tracking experiment explored the gaze behavior of deaf individuals when perceiving language in spoken and sign language only, and in sign-supported speech (SSS). Participants were deaf (n = 25) and hearing (n = 25) Spanish adolescents. Deaf students were prelingually profoundly deaf individuals with cochlear implants (CIs) used by age 5 or earlier, or prelingually profoundly deaf native signers with deaf parents. The effectiveness of SSS has rarely been tested within the same group of children for discourse-level comprehension. Here, video-recorded texts, including spatial descriptions, were alternately transmitted in spoken language, sign language and SSS. The capacity of these communicative systems to equalize comprehension in deaf participants with that of spoken language in hearing participants was tested. Within-group analyses of deaf participants tested if the bimodal linguistic input of SSS favored discourse comprehension compared to unimodal languages. Deaf participants with CIs achieved equal comprehension to hearing controls in all communicative systems while deaf native signers with no CIs achieved equal comprehension to hearing participants if tested in their native sign language. Comprehension of SSS was not increased compared to spoken language, even when spatial information was communicated. Eye movements of deaf and hearing participants were tracked and data of dwell times spent looking at the face or body area of the sign model were analyzed. Within-group analyses focused on differences between native and non-native signers. Dwell times of hearing participants were equally distributed across upper and lower areas of the face while deaf participants mainly looked at the mouth area; this could enable information to be obtained from mouthings in sign language and from lip-reading in SSS and spoken language. Few fixations were directed toward the signs, although these were more frequent when spatial language was transmitted. Both native and non-native signers looked mainly at the face when perceiving sign language, although non-native signers looked significantly more at the body than native signers. This distribution of gaze fixations suggested that deaf individuals – particularly native signers – mainly perceived signs through peripheral vision.

The Development of Sensitivity to Grammatical Violations in American Sign Language: Native Versus Nonnative Signers

AbstractFactors influencing native and nonnative signers’ syntactic judgment ability in American Sign Language (ASL) were explored for 421 deaf students aged 7;6–18;5. Predictors for syntactic knowledge were chronological age, age of entering a school for the deaf, gender, and additional learning disabilities. Mixed‐effects linear modeling analysis revealed main effects of each predictor and an interaction between signing status and learning disability. The native signers showed typical syntactic development that varied by chronological age, gender, additional learning disabilities, and age of entering a deaf school. In contrast, the syntactic development of nonnative signers was more variable. It was less tightly related to chronological age and more strongly influenced by the age at which they had entered the school where assessment occurred, which was highly related to length of exposure to a sign language.

American Sign Language Syntax and Analogical Reasoning Skills Are Influenced by Early Acquisition and Age of Entry to Signing Schools for the Deaf.

Failing to acquire language in early childhood because of language deprivation is a rare and exceptional event, except in one population. Deaf children who grow up without access to indirect language through listening, speech-reading, or sign language experience language deprivation. Studies of Deaf adults have revealed that late acquisition of sign language is associated with lasting deficits. However, much remains unknown about language deprivation in Deaf children, allowing myths and misunderstandings regarding sign language to flourish. To fill this gap, we examined signing ability in a large naturalistic sample of Deaf children attending schools for the Deaf where American Sign Language (ASL) is used by peers and teachers. Ability in ASL was measured using a syntactic judgment test and language-based analogical reasoning test, which are two sub-tests of the ASL Assessment Inventory. The influence of two age-related variables were examined: whether or not ASL was acquired from birth in the home from one or more Deaf parents, and the age of entry to the school for the Deaf. Note that for non-native signers, this latter variable is often the age of first systematic exposure to ASL. Both of these types of age-dependent language experiences influenced subsequent signing ability. Scores on the two tasks declined with increasing age of school entry. The influence of age of starting school was not linear. Test scores were generally lower for Deaf children who entered the school of assessment after the age of 12. The positive influence of signing from birth was found for students at all ages tested (7;6–18;5 years old) and for children of all age-of-entry groupings. Our results reflect a continuum of outcomes which show that experience with language is a continuous variable that is sensitive to maturational age.

The relationship between working memory capacity and simultaneous interpreting performance

This experimental study investigated the relationship between signed language interpreters’ working memory capacity (WMC) and their simultaneous interpreting performance. Thirty-one professional Auslan (Australian Sign Language)/English interpreters participated: 14 native signers and 17 non-native signers. They completed simultaneous interpreting tasks from English into Auslan and vice versa, an English listening span task and an Auslan working memory span task; each interpreting task was followed by a short semi-structured interview. Quantitative results for the sample as a whole showed no significant correlations between bilingual WMC and overall simultaneous interpreting performance in either direction. The same trend was established for both the native signers and the non-native signers, considered as two separate groups. The findings thus suggest that professional signed language interpreters’ WMC as measured by complex span tasks is not closely associated with the overall quality of their simultaneous interpreting performance. Data regarding educational and professional background showed mixed patterns in relation to participants’ interpreting performance in each language direction. In the interviews, participants reported various triggers of cognitive overload in the simultaneous interpreting tasks (e.g. numbers, lists of items, a long time lag, dense information, fatigue) and mentioned their coping strategies (e.g. strategic omissions, summarization, generalization, adjusting time lag).

Directionality in Signed Language Interpreting

This mixed methods study investigated the effects of directionality (language direction) and age of signed language acquisition on the simultaneous interpreting performance of professional English/Auslan (Australian Sign Language) interpreters, who comprised native signers and non-native signers. Each participant interpreted presentations simultaneously from English into Auslan, and vice versa, with each task followed by a brief semi-structured interview. Unlike a similar study, results reveal no significant differences between the native signers’ English-to-Auslan simultaneous interpreting performance and their Auslan-to-English simultaneous interpreting performance, suggesting that balanced bilingual interpreters are free from the rule of directionality. Although this finding held true for the non-native signers, results indicate a need for the non-native signers to continue to enhance their signed language (L2) competence. Furthermore, although the native signers were similar to the non-native signers in overall simultaneous interpreting performance in each language direction, the native signers were significantly superior to the non-native signers in both the target text features and delivery features of English-to-Auslan simultaneous interpreting performance. These findings also suggest that the non-native signers need to further improve their signed language (L2) proficiency. Nevertheless, an analysis of the qualitative interview data reveals that the professional interpreters perceived distinct challenges that were unique to each language direction.

American Sign Language Comprehension Test: A Tool for Sign Language Researchers.

The American Sign Language Comprehension Test (ASL-CT) is a 30-item multiple-choice test that measures ASL receptive skills and is administered through a website. This article describes the development and psychometric properties of the test based on a sample of 80 college students including deaf native signers, hearing native signers, deaf non-native signers, and hearing ASL students. The results revealed that the ASL-CT has good internal reliability (α = 0.834). Discriminant validity was established by demonstrating that deaf native signers performed significantly better than deaf non-native signers and hearing native signers. Concurrent validity was established by demonstrating that test results positively correlated with another measure of ASL ability (r = .715) and that hearing ASL students' performance positively correlated with the level of ASL courses they were taking (r = .726). Researchers can use the ASL-CT to characterize an individual's ASL comprehension skills, to establish a minimal skill level as an inclusion criterion for a study, to group study participants by ASL skill (e.g., proficient vs. nonproficient), or to provide a measure of ASL skill as a dependent variable.

Deaf children's non-verbal working memory is impacted by their language experience.

Several recent studies have suggested that deaf children perform more poorly on working memory tasks compared to hearing children, but these studies have not been able to determine whether this poorer performance arises directly from deafness itself or from deaf children's reduced language exposure. The issue remains unresolved because findings come mostly from (1) tasks that are verbal as opposed to non-verbal, and (2) involve deaf children who use spoken communication and therefore may have experienced impoverished input and delayed language acquisition. This is in contrast to deaf children who have been exposed to a sign language since birth from Deaf parents (and who therefore have native language-learning opportunities within a normal developmental timeframe for language acquisition). A more direct, and therefore stronger, test of the hypothesis that the type and quality of language exposure impact working memory is to use measures of non-verbal working memory (NVWM) and to compare hearing children with two groups of deaf signing children: those who have had native exposure to a sign language, and those who have experienced delayed acquisition and reduced quality of language input compared to their native-signing peers. In this study we investigated the relationship between NVWM and language in three groups aged 6–11 years: hearing children (n = 28), deaf children who were native users of British Sign Language (BSL; n = 8), and deaf children who used BSL but who were not native signers (n = 19). We administered a battery of non-verbal reasoning, NVWM, and language tasks. We examined whether the groups differed on NVWM scores, and whether scores on language tasks predicted scores on NVWM tasks. For the two executive-loaded NVWM tasks included in our battery, the non-native signers performed less accurately than the native signer and hearing groups (who did not differ from one another). Multiple regression analysis revealed that scores on the vocabulary measure predicted scores on those two executive-loaded NVWM tasks (with age and non-verbal reasoning partialled out). Our results suggest that whatever the language modality—spoken or signed—rich language experience from birth, and the good language skills that result from this early age of acquisition, play a critical role in the development of NVWM and in performance on NVWM tasks.

Deaf native signers are better readers than nonnative signers: myth or truth?

The central aim of this study was to clarify whether sign language (SL) nativeness is a significant factor in determining prelingually deaf individuals' reading skills and whether its contribution is modified by the reader's orthographic background. A second aim was to elucidate similarities and differences between native and nonnative signers in processing written information at different processing levels in order to understand how SL nativeness sustains the reading process, if at all. Participants were 176 students with prelingual deafness recruited from two education levels (6th-7th graders and 9th-10th graders) and three orthographic backgrounds (Hebrew, German, and Turkish). Sixty-six students were native and the remainder nonnative signers. They were tested with a battery of eight experimental paradigms, each assessing their information processing skills in a specific reading-related or reading-unrelated domain. Findings corroborate SL nativeness enhancing the reading process in some regard. However, its contribution was not found to scaffold the structural processing of a written text to turn reading into a tool for learning. Rather, gains were restricted to facilitating processing written words from a perceptual to a conceptual level. Evidence suggests that compared with other determining factors, the contribution of SL nativeness to proficient reading may be rather marginal.

Electrophysiological correlates of cross-linguistic semantic integration in hearing signers: N400 and LPC

We explored semantic integration mechanisms in native and non-native hearing users of sign language and non-signing controls. Event-related brain potentials (ERPs) were recorded while participants performed a semantic decision task for priming lexeme pairs. Pairs were presented either within speech or across speech and sign language. Target-related ERP responses were subjected to principal component analyses (PCA), and neurocognitive basis of semantic integration processes were assessed by analyzing the N400 and the late positive complex (LPC) components in response to spoken (auditory) and signed (visual) antonymic and unrelated targets. Semantically-related effects triggered across modalities would indicate a similar tight interconnection between the signers׳ two languages like that described for spoken language bilinguals. Remarkable structural similarity of the N400 and LPC components with varying group differences between the spoken and signed targets were found. The LPC was the dominant response. The controls׳ LPC differed from the LPC of the two signing groups. It was reduced to the auditory unrelated targets and was less frontal for all the visual targets. The visual LPC was more broadly distributed in native than non-native signers and was left-lateralized for the unrelated targets in the native hearing signers only. Semantic priming effects were found for the auditory N400 in all groups, but only native hearing signers revealed a clear N400 effect to the visual targets. Surprisingly, the non-native signers revealed no semantically-related processing effect to the visual targets reflected in the N400 or the LPC; instead they appeared to rely more on visual post-lexical analyzing stages than native signers. We conclude that native and non-native signers employed different processing strategies to integrate signed and spoken semantic content. It appeared that the signers׳ semantic processing system was affected by group-specific factors like language background and/or usage.

Bilingual working memory capacity of professional Auslan / English interpreters

This study investigated bilingual working memory capacity (WMC) of 31 professional Auslan (Australian Sign Language)/English interpreters: 14 native signers and 17 non-native signers. Participants completed an English listening span task and then an Auslan working memory (WM) span task, each task followed by a brief interview. The native signers were similar to the non-native signers not only in English WMC, but also in Auslan WMC. There was no significant difference between WMC in English and Auslan when native and non-native signers were assessed as a single group. The study also found a moderate to strong, positive correlation between the interpreters’ English WMC and Auslan WMC, suggesting that both WM span tasks tapped into similar cognitive resources. In the interviews, interpreters said that they used multiple strategies to retain the to-be-remembered words/signs. The qualitative data also indicate that WM span tasks like these involve online retention of unrelated words/signs, whereas simultaneous interpreting requires temporary storage of meaningful and coherent concepts.

Deaf readers’ response to syntactic complexity: Evidence from self-paced reading

This study was designed to determine the feasibility of using self-paced reading methods to study deaf readers and to assess how deaf readers respond to two syntactic manipulations. Three groups of participants read the test sentences: deaf readers, hearing monolingual English readers, and hearing bilingual readers whose second language was English. In Experiment 1, the participants read sentences containing subject-relative or object-relative clauses. The test sentences contained semantic information that would influence online processing outcomes (Traxler, Morris, & Seely Journal of Memory and Language 47: 69-90, 2002; Traxler, Williams, Blozis, & Morris Journal of Memory and Language 53: 204-224, 2005). All of the participant groups had greater difficulty processing sentences containing object-relative clauses. This difficulty was reduced when helpful semantic cues were present. In Experiment 2, participants read active-voice and passive-voice sentences. The sentences were processed similarly by all three groups. Comprehension accuracy was higher in hearing readers than in deaf readers. Within deaf readers, native signers read the sentences faster and comprehended them to a higher degree than did nonnative signers. These results indicate that self-paced reading is a useful method for studying sentence interpretation among deaf readers.