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The emergence of a new sign language since the late 1970s in Nicaragua enables us to capture the effects of successive cohorts of learners on an emerging grammar and to observe how elements are reshaped from one form and function to another. Here we document the contrastive use of a device that has been found to be central to the grammars of sign languages: the spatial modulation of signs. In Nicaraguan Sign Language, this device has two primary functions: expressing the participants of events (that is, indicating who), and describing locations and orientations of referents (that is, indicating where). We ask whether the two uses reduce to a single construction type, or if the more abstract who construction derived from the more iconic and concrete where construction. We compare the first two successive cohorts of deaf signers to acquire the language in its first decade. We find that as learners created new constructions to meet the new functions, they did not simply apply an already developed form more broadly, nor did they develop the more abstract application from the more iconic one. Instead, the more abstract who construction appears to have conventionalized first. Thus, the forms either emerged independently, or split very early in the 1980s, before either had developed as a consistently applied form. Key Words Language birth * Language change * Language emergence * Spatial language DOI: 10.1159/000321455

American Sign Language (ASL) uses the face to express grammar and inflection, in addition to emotion. Research in this area has mostly used photographic stimuli. The purpose of this paper is to present data on how deaf signers and hearing non-signers recognize and categorize a variety of communicative facial expressions in ASL using dynamic stimuli rather than static pictures. Stimuli included six expression types chosen because they share overt similarities but express different content. Hearing participants were more accurate in their categorizations but expressed overall lower confidence regarding their performance. Keywords ASL * Dynamic facial expressions * Categorization * Accuracy * Confidence

In light of the controversy about the linguistic properties of chimpanzee signing behavior, the recent sign use of 5 chimpanzees (Pan troglodytes) with long histories of sign use was analyzed while they interacted with longtime human companions. Four corpora from 1992 to 1999 consisting of 3,448 sign utterances were examined. The chimpanzees predominantly used object and action signs. There was no evidence for semantic or syntactic structure in combinations of signs. Longer combinations showed repetition and stringing of object and action signs. The chimpanzees mostly signed with an acquisitive motivation. Requests for objects and actions were the predominant communicative intentions of the sign utterances, though naming and answering also occurred. This recent sign use shows multiple differences with (early) human language.

Despite the constantly varying stream of sensory information that surrounds us, we humans can discern the small building blocks of words that constitute language (phonetic forms) and perceive them categorically (categorical perception, CP). Decades of controversy have prevailed regarding what is at the heart of CP, with many arguing that it is due to domain-general perceptual processing and others that it is determined by the existence of domain-specific linguistic processing. What is most key: perceptual or linguistic patterns? Here, we study whether CP occurs with soundless handshapes that are nonetheless phonetic in American Sign Language (ASL), in signers and nonsigners. Using innovative methods and analyses of identification and, crucially, discrimination tasks, we found that both groups separated the soundless handshapes into two classes perceptually but that only the ASL signers exhibited linguistic CP. These findings suggest that CP of linguistic stimuli is based on linguistic categorization, rather than on purely perceptual categorization.

Long-term use of a sign language may enhance visual abilities. Deaf signers consistently outscore their hearing nonsigning counterparts on visual memory tests. In a similar vein, the long-term use of a logographic script, Chinese characters appears to boost visual memory. Both learning a sign language and mastering Chinese characters involve a relatively complex task of visual recognition and memory. This review of the literature suggests that daily use of either a sign language, one not based on sound, or Chinese characters, a script which maps language at the word level rather than at the phonemic level, may facilitate recall of visual forms.

We report a sign length effect in deaf users of American Sign Language that is analogous to the word length effect for speech. Lists containing long signs (signs that traverse relatively long distances) produced poorer memory performance than did lists of short signs (signs that do not change in location). Further, this length effect was eliminated by articulatory suppression (repetitive motion of the hands), and articulatory suppression produced an overall drop in performance. The pattern of results, together with previous findings (Wilson & Emmorey, 1997), provides evidence for a working memory system for sign language that consists of a phonological storage buffer and an articulatory rehearsal mechanism. This indicates a close equivalence of structure between working memory for sign language and working memory for speech. The implications of this equivalence are discussed.

N. Masataka (1996) reported results of an experiment in which 6-month-old deaf infants were presented with videotapes that showed 5 identical scripts signed in Japanese Sign Language by 5 deaf mothers toward their deaf infants or toward their deaf friends. The experiment demonstrated that infants showed greater attentional and affective responsiveness to infant-directed signing than to adult-directed signing. The present study explored the possibility that this same phenomenon might extend to hearing infants who have never been exposed to signed language. When the same stimulus tape as used previously was presented to 45 six-month-old hearing infants, they too showed greater attentional and affective responsiveness to infant-directed sign than to adult-directed sign. This fact suggests that infants are prepared to detect sign motherese characteristics without specific experience in the modality.

Communication strategies for deaf children should focus on the development of age-appropriate language. A combination of sign and spoken language is the most appropriate communication strategy for deaf children. Families should adopt supportive and positive, rather than directive communication styles, fostering an interactive environment for child's language development. Language development in school-age children, role of language preference, and some other related issues are discussed. Psychological assessment and therapeutic intervention strategies are described.

The study explored the possibility that characteristics in perception of speech sounds found in pre-verbal hearing infants might extend to perception of signed languages in congenitally deaf infants during the same period. Participants were deaf mothers (N = 17) and their deaf infants; 5 of the dyads were used to prepare the stimulus tape later shown to the remaining 12 dyads. To develop the tape, the 5 mothers were observed when reciting identical scripts in Japanese Sign Language either toward their infants or toward their deaf friends. The videotape showed that mothers used signs at a significantly slower tempo when interacting with their infants than when interacting with their friends, often repeating the same sign and exaggerating the movements associated with each sign somewhat. When the stimulus tape was presented, deaf infants showed greater attentional and affective responsiveness to infant-directed signing than to adult-directed signing. The fact suggests that human infants may be equally predisposed to attend to motherese characteristics in speech or sign.

How well can a sequence of frames be represented by a subset of the frames? Video sequences of American Sign language (ASL) were investigated in two modes: dynamic (ordinary video) and static (frames printed side by side on the display). An activity index was used to choose critical frames at event boundaries, times when the difference between successive frames is at a local minimum. Sign intelligibility was measured for 32 experienced ASL signers who viewed individual signs. For full gray-scale dynamic signs activity-index subsampling yielded sequences that were significantly more intelligible than when every mth frame was chosen. This result was even more pronounced for static images. For binary images, the relative advantage of activity subsampling was smaller. We conclude that event bounardies can be defined computationally and that subsampling from even boundaries is better than choosing at regular intervals.

It has long been postulated that language is not purely learned, but arises from an interaction between environmental exposure and innate abilities. The innate component becomes more evident in rare situations in which the environment is markedly impoverished. The present study investigated the language production of a generation of deaf Nicaraguans who had not been exposed to a developed language. We examined the changing use of early linguistic structures (specifically, spatial modulations) in a sign language that has emerged since the Nicaraguan group first came together. In under two decades, sequential cohorts of learners systematized the grammar of this new sign language. We examined whether the systematicity being added to the language stems from children or adults; our results indicate that such changes originate in children aged 10 and younger. Thus, sequential cohorts of interacting young children collectively possess the capacity not only to learn, but also to create, language.

Evidence from studies of the processing of topographic and classifier constructions in sign language sentences provides a model of how a mental scene description can be represented linguistically, but it also raises questions about how this can be related to spatial linguistic descriptions in spoken languages and their processing. This in turn provides in sights into models of the evolution of language.

In two studies, we find that native and non-native acquisition show different effects on sign language processing. Subjects were all born deaf and used sign language for interpersonal communication, but first acquired it at ages ranging from birth to 18. In the first study, deaf signers shadowed (simultaneously watched and reproduced) sign language narratives given in two dialects, American Sign Language (ASL) and Pidgin Sign English (PSE), in both good and poor viewing conditions. In the second study, deaf signers recalled and shadowed grammatical and ungrammatical ASL sentences. In comparison with non-native signers, natives were more accurate, comprehended better, and made different kinds of lexical changes; natives primarily changed signs in relation to sign meaning independent of the phonological characteristics of the stimulus. In contrast, non-native signers primarily changed signs in relation to the phonological characteristics of the stimulus independent of lexical and sentential meaning. Semantic lexical changes were positively correlated to processing accuracy and comprehension, whereas phonological lexical changes were negatively correlated. The effects of non-native acquisition were similar across variations in the sign dialect, viewing condition, and processing task. The results suggest that native signers process lexical structure automatically, such that they can attend to and remember lexical and sentential meaning. In contrast, non-native signers appear to allocate more attention to the task of identifying phonological shape such that they have less attention available for retrieval and memory of lexical meaning.

In this study, we investigated bases for encoding linguistic stimuli in short-term memory. Past research has provided evidence for both phonological (sound-based) and cherological (sign-based) encoding, the former typically found with hearing subjects and the latter with deaf users of sign language. In the present experiment, encoding capabilities were delineated from encoding preferences, using 58 subjects comprising six groups differing in hearing ability and linguistic experience. Phonogically related, cherologically related, and control lists were presented orally, manually, or through both modalities simultaneously. Recall performance indicated that individuals encode flexibly, the code actually used being biased by incoming stimulus characteristics. Subjects with both sign and speech experience recalled simultaneous presentations better than ones presented orally or manually alone, which reveals the occurrence of enhanced encoding as a function of linguistic experience. Total linguistic experience appeared to determine recall accuracy following different types of encoding, rather than determining the encoding basis used.

This commentary supports MacNeilage's dismissal of an evolutionary development from sign language to spoken language but presents evidence of a feature in sign language (echo phonology) that links iconic signs to abstract vocal syllables. These data provide an insight into possible mechanism by which iconic manual gestures accompanied by vocalisation could have provided a route for the evolution of spoken language with its characteristically arbitrary form-meaning relationship.

This study replicated the 1984 work of Miller who reported a normal mean Verbal IQ of profoundly deaf students. To 27 profoundly deaf students the WISC - R Verbal Scale was administered using one of three signed language systems. The means do not support Miller's findings and raise some doubt about the mediating effects of language systems among profoundly deaf students.