Alan Langus

Cognitive Systems Struggling for Word Order.

We argue that the grammatical diversity observed among the worlds languages emerges from the struggle between individual cognitive systems trying to impose their preferred structure on human language. We investigate the cognitive bases of the two most common word orders in the worlds languages: SOV (Subject-Object-Verb) and SVO. Evidence from language change, grammaticalization, stability of order, and theoretical arguments, indicates a syntactic preference for SVO. The reason for the prominence of SOV languages is not as clear. In two gesture-production experiments and one gesture comprehension experiment, we show that SOV emerges as the preferred constituent configuration in participants whose native languages (Italian and Turkish) have different word orders. We propose that improvised communication does not rely on the computational system of grammar. The results of a fourth experiment, where participants comprehended strings of prosodically flat words in their native language, shows that the computational system of grammar prefers the orthogonal Verb-Object orders.

Prosody in the hands of the speaker

In everyday life, speech is accompanied by gestures. In the present study, two experiments tested the possibility that spontaneous gestures accompanying speech carry prosodic information. Experiment 1 showed that gestures provide prosodic information, as adults are able to perceive the congruency between low-pass filtered—thus unintelligible—speech and the gestures of the speaker. Experiment 2 shows that in the case of ambiguous sentences (i.e., sentences with two alternative meanings depending on their prosody) mismatched prosody and gestures lead participants to choose more often the meaning signaled by gestures. Our results demonstrate that the prosody that characterizes speech is not a modality specific phenomenon: it is also perceived in the spontaneous gestures that accompany speech. We draw the conclusion that spontaneous gestures and speech form a single communication system where the suprasegmental aspects of spoken language are mapped to the motor-programs responsible for the production of both speech sounds and hand gestures.

Mice discriminate between stationary and moving 2D shapes: application to the object recognition task to increase attention.

Selective attention can be assessed with the novel object recognition (NOR) test. In the standard version of this test the selection of objects to be used is critical. We created a modified version of NOR, the virtual object recognition test (VORT) in mice, where the 3D objects were replaced with highly discriminated geometrical shapes and presented on two 3.5-inch widescreen displays. No difference in the discrimination index (from 5min to 96h of inter-trial) was found between NOR and VORT. Scopolamine and mecamylamine decreased the discrimination index. Conversely, the discrimination index increased when nicotine was given to mice. No further improvement in the discrimination index was observed when nicotine was injected in mice presented with highly discriminable shapes. To test the possibility that object movements increased mices attention in the VORT, different movements were applied to the same geometrical shapes previously presented. Mice were able to distinguish among different movements (horizontal, vertical, oblique). Notably, the shapes previously found not distinguishable when stationary were better discriminated when moving. Collectively, these findings indicate that VORT, based on virtual geometric simple shapes, offers the possibility to obtain rapid information on amnesic/pro-amnestic potential of new drugs. The introduction of motion is a strong cue that makes the task more valuable to study attention.

Rhythm in language acquisition

HighlightsThe rhythm of spoken language is structured hierarchically.Rhythm is universal on the segmental level, the level of metric feet and phonological phrases.Human infants are sensitive to speech rhythm early in development and may use this sensitivity for breaking into the speech code. Abstract Spoken language is governed by rhythm. Linguistic rhythm is hierarchical and the rhythmic hierarchy partially mimics the prosodic as well as the morpho‐syntactic hierarchy of spoken language. It can thus provide learners with cues about the structure of the language they are acquiring. We identify three universal levels of linguistic rhythm – the segmental level, the level of the metrical feet and the phonological phrase level – and discuss why primary lexical stress is not rhythmic. We survey experimental evidence on rhythm perception in young infants and native speakers of various languages to determine the properties of linguistic rhythm that are present at birth, those that mature during the first year of life and those that are shaped by the linguistic environment of language learners. We conclude with a discussion of the major gaps in current knowledge on linguistic rhythm and highlight areas of interest for future research that are most likely to yield significant insights into the nature, the perception, and the usefulness of linguistic rhythm.

Co-occurrence statistics as a language-dependent cue for speech segmentation

To what extent can language acquisition be explained in terms of different associative learning mechanisms? It has been hypothesized that distributional regularities in spoken languages are strong enough to elicit statistical learning about dependencies among speech units. Distributional regularities could be a useful cue for word learning even without rich language-specific knowledge. However, it is not clear how strong and reliable the distributional cues are that humans might use to segment speech. We investigate cross-linguistic viability of different statistical learning strategies by analyzing child-directed speech corpora from nine languages and by modeling possible statistics-based speech segmentations. We show that languages vary as to which statistical segmentation strategies are most successful. The variability of the results can be partially explained by systematic differences between languages, such as rhythmical differences. The results confirm previous findings that different statistical learning strategies are successful in different languages and suggest that infants may have to primarily rely on non-statistical cues when they begin their process of speech segmentation.

Listening Natively Across Perceptual Domains

Our native tongue influences the way we perceive other languages. But does it also determine the way we perceive nonlinguistic sounds? The authors investigated how speakers of Italian, Turkish, and Persian group sequences of syllables, tones, or visual shapes alternating in either frequency or duration. We found strong native listening effects with linguistic stimuli. Speakers of Italian grouped the linguistic stimuli differently from speakers of Turkish and Persian. However, speakers of all languages showed the same perceptual biases when grouping the nonlinguistic auditory and the visual stimuli. The shared perceptual biases appear to be determined by universal grouping principles, and the linguistic differences caused by prosodic differences between the languages. Although previous findings suggest that acquired linguistic knowledge can either enhance or diminish the perception of both linguistic and nonlinguistic auditory stimuli, we found no transfer of native listening effects across auditory domains or perceptual modalities. (PsycINFO Database Record

A new perspective on word order preferences: the availability of a lexicon triggers the use of SVO word order

Word orders are not distributed equally: SOV and SVO are the most prevalent among the worlds languages. While there is a consensus that SOV might be the “default” order in human languages, the factors that trigger the preference for SVO are still a matter of debate. Here we provide a new perspective on word order preferences that emphasizes the role of a lexicon. We propose that while there is a tendency to favor SOV in the case of improvised communication, the exposure to a shared lexicon makes it possible to liberate sufficient cognitive resources to use syntax. Consequently SVO, the more efficient word order to express syntactic relations, emerges. To test this hypothesis, we taught Italian (SVO) and Persian (SOV) speakers a set of gestures and later asked them to describe simple events. Confirming our prediction, results showed that in both groups a consistent use of SVO emerged after acquiring a stable gesture repertoire.

Language development in infants: What do humans hear in the first months of life?

Abstract In this article we discuss experimental work on language acquisition that we have carried out in recent years. We first describe the most common methods used in infant research, then we concentrate on linguistic rhythm and the aspects of language that might be learned in the first year of life on the basis of signals contained in the speech stream. These include the basic level of rhythm carried by the two most basic phonological categories of consonants and vowels, and rhythmic alternation at the phrase level and its signal to syntax. Because linguistic rhythm is one of the first aspects of language that infants perceive and represent, the research discussed may help to diagnose hearing problems and lead to new ways of training individuals with speech impairments.

Transitional probabilities count more than frequency, but might not be used for memorization

Learners often need to extract recurring items from continuous sequences, in both vision and audition. The best-known example is probably found in word-learning, where listeners have to determine where words start and end in fluent speech. This could be achieved through universal and experience-independent statistical mechanisms, for example by relying on Transitional Probabilities (TPs). Further, these mechanisms might allow learners to store items in memory. However, previous investigations have yielded conflicting evidence as to whether a sensitivity to TPs is diagnostic of the memorization of recurring items. Here, we address this issue in the visual modality. Participants were familiarized with a continuous sequence of visual items (i.e., arbitrary or everyday symbols), and then had to choose between (i) high-TP items that appeared in the sequence, (ii) high-TP items that did not appear in the sequence, and (iii) low-TP items that appeared in the sequence. Items matched in TPs but differing in (chunk) frequency were much harder to discriminate than items differing in TPs (with no significant sensitivity to chunk frequency), and learners preferred unattested high-TP items over attested low-TP items. Contrary to previous claims, these results cannot be explained on the basis of the similarity of the test items. Learners thus weigh within-item TPs higher than the frequency of the chunks, even when the TP differences are relatively subtle. We argue that these results are problematic for distributional clustering mechanisms that analyze continuous sequences, and provide supporting computational results. We suggest that the role of TPs might not be to memorize items per se, but rather to prepare learners to memorize recurring items once they are presented in subsequent learning situations with richer cues.

Rhythm on Your Lips

The Iambic-Trochaic Law (ITL) accounts for speech rhythm, grouping of sounds as either Iambs—if alternating in duration—or Trochees—if alternating in pitch and/or intensity. The two different rhythms signal word order, one of the basic syntactic properties of language. We investigated the extent to which Iambic and Trochaic phrases could be auditorily and visually recognized, when visual stimuli engage lip reading. Our results show both rhythmic patterns were recognized from both, auditory and visual stimuli, suggesting that speech rhythm has a multimodal representation. We further explored whether participants could match Iambic and Trochaic phrases across the two modalities. We found that participants auditorily familiarized with Trochees, but not with Iambs, were more accurate in recognizing visual targets, while participants visually familiarized with Iambs, but not with Trochees, were more accurate in recognizing auditory targets. The latter results suggest an asymmetric processing of speech rhythm: in auditory domain, the changes in either pitch or intensity are better perceived and represented than changes in duration, while in the visual domain the changes in duration are better processed and represented than changes in pitch, raising important questions about domain general and specialized mechanisms for speech rhythm processing.