Syllable Sequences Research Articles

How Well Does Diadochokinetic Task Performance Predict Articulatory Imprecision? Differentiating Individuals with Parkinson’s Disease from Control Subjects

Objective: To investigate whether syllables produced in an oral diadochokinetic (DDK) task may be quantified so that persons with Parkinson’s disease (PD) perceived to have reduced articulatory precision when reading may be correctly identified using that quantification. Patients and Methods: Syllable sequences from 38 speakers with PD and 38 gender- and age-matched control speakers (normal controls [NC]) were quantified acoustically and evaluated in terms of (1) the speakers’ ability to accurately predict speaker group membership (PD or NC) and (2) their ability to predict reduced/non-reduced articulatory precision. Results: A balanced accuracy of 80–93% in predicting speaker group membership was achieved. The best measures were related to the proportion of a syllable made up of a vowel, amplitude slope and syllable-to-syllable variation in duration and amplitude. The best material was that based on /ka/. Reduced articulatory precision was accurately predicted from DDK measures in 89% of the samples. Release-transient prominence and voicing during the onset of plosives were particularly strong predictors. Conclusions: DDK sequences can predict articulatory imprecision as observed in another speech task. The linking of performance across speech tasks probably requires measures of stability in syllable durations and amplitudes, as well as measures of subsyllabic acoustic features.

Muzikinis anglų kalbos ritmo mokymas

[full article, abstract in English; abstract in Lithuanian] The research into the perception and production of English rhythm has been a subject of argument among linguists and language educators for decades. English has traditionally been ascribed to the group of stress-timed rhythm languages as opposed to syllable-timed languages (Pike, 1945; Abercrombie, 1967; Ladefoged, 1975) and even though several scholars find this typological classification of languages contraversive (e.g. Dauer, 1987), certain reliable stress-timed acoustic cues remain relevant to EFL learners and help acquiring the natural sound of English. The particular rhythmic cues determine the alternation of weak and strong syllable sequences as well as the implication of certain aspects of connected speech. The EFL learners need to develop the feel for this specific English rhythm and educators worldwide suggest various natural input strategies and practice techniques. This particular paper argues for the implementation of music in order to develop the feel for English rhythm, since there is emerging evidence that language and music share a number of features at evolutionary, cognitive as well as sensory perceptual levels (Patel, 2003; Mithen, 2005; Jackendoff, 2009). Moreover, the two capacities of the human mind are similar in their expressive features as well as their hierarchic structure including the prosody: stress, meter and rhythm. Scholars in the field argue that EFL learners may benefit from this cross-domain influence, since the interaction of linguistic stress and musical meter enhances the perception and production of natural English rhythm (Besson et al., 2008). The particular experimental study was carried out on a cohort of 29 non-native English students of different linguistic backgrounds, who were exposed to selected sentence patterns through musically rhythmical expertise. The results suggested benefits in English speech rhythm: they demonstrated a better skill in stressing, strong / weak syllable production and recognition as well as vowel reduction. Keywords : rhythm, rhythmic typology, stress-timing, vowel reduction, music instruction DOI: https://doi.org/10.15823/zz.2018.19

Reversal shift in phonotactic learning during language production: Evidence for incremental learning

Abstract Speakers implicitly learn novel phonotactic patterns while producing strings of syllables. The learning is revealed in their speech errors. For example, if /f/ is artificially restricted to the syllable onset position and /s/ is restricted to the coda position, speakers’ slips will respect these constraints, demonstrating learning. The mechanism behind this learning was investigated by reversal shift. In two experiments, speakers produced syllable sequences for 32 trials in which one consonant was constrained to be an onset and one, a coda. Then for the next 32 trials, the constraints were reversed; for example, /f/ is now a coda and /s/ an onset. Over a third block of 32 trials, the constraints were reversed again back to the original rule. The learning of the reversed rules was slow in comparison to rapid learning of the original rule, providing evidence that the underlying mechanism is incremental. To learn a reversed rule, first one must unlearn the original association before making progress on the new rule. This pattern of rapid initial learning and slow reversal learning was replicated in a nonspeech analogue of the syllable production task. Participants pushed sequences of buttons, in which finger presses corresponded to consonants and thumb presses to vowels. A control experiment found that non-reversal shifts between blocks are easily learned, showing that the difficulty is specifically with reversal shifts. A final experiment provided evidence that learning in these experiments is greater when productions are more errorful.

Perceptual Tuning Influences Rule Generalization: Testing Humans With Monkey-Tailored Stimuli.

Comparative research investigating how nonhuman animals generalize patterns of auditory stimuli often uses sequences of human speech syllables and reports limited generalization abilities in animals. Here, we reverse this logic, testing humans with stimulus sequences tailored to squirrel monkeys. When test stimuli are familiar (human voices), humans succeed in two types of generalization. However, when the same structural rule is instantiated over unfamiliar but perceivable sounds within squirrel monkeys’ optimal hearing frequency range, human participants master only one type of generalization. These findings have methodological implications for the design of comparative experiments, which should be fair towards all tested species’ proclivities and limitations.

Implicit versus explicit mechanisms of vocabulary learning and consolidation

Abstract Previous research has suggested that integration of novel words into lexical competition benefits from a consolidation delay containing a period of sleep (Dumay & Gaskell, 2007). However, a recent study argued that learning novel words via a relatively implicit Hebb repetition task leads to later lexical integration independently of sleep (Szmalec, Page, & Duyck, 2012). It is not clear whether this different time course of lexical integration is a consequence of the learning method chosen, as opposed to other between study differences. Four experiments directly compared the learning of novel words using explicit and implicit methods, namely phoneme monitoring on isolated tokens vs. Hebb repetition of syllable sequences. The impact of the learning was tested at a range of later time-points using two tests of explicit knowledge (recognition and recall) and a test of lexical integration (pause detection on related existing words). Between experiments, we also manipulated exposure frequency, the impact of syllable grouping cues in Hebb repetition and the level of mismatch between novel and real words. The results suggested that learning novel words via Hebb sequence repetition does not confer a benefit on lexical integration prior to or after sleep. We observed an engagement in lexical competition only in the case where a good level of explicit training was followed by a consolidation delay. Recognition and recall performance was generally poorer for Hebb learning. We conclude that Hebb-style implicit learning of words does not allow consolidation processes to be bypassed in lexical integration.

Functional and Structural Brain Plasticity in Adult Onset Single-Sided Deafness.

Single-sided deafness (SSD) or profound unilateral hearing loss obligates the only serviceable ear to capture all acoustic information. This loss of binaural function taxes cognitive resources for accurate listening performance, especially under adverse environments or challenging tasks. We hypothesized that adults with SSD would manifest both functional and structural brain plasticity compared to controls with normal binaural hearing. We evaluated functional alterations using magnetoencephalographic imaging (MEGI) of brain activation during performance of a moderately difficult auditory syllable sequence reproduction task and assessed structural integrity using diffusion tensor imaging (DTI). MEGI showed the SSD cohort to have increased induced oscillations in the theta band over the left superior temporal cortex and decreased induced gamma band oscillations over the frontal and parietal cortices between 175 and 475 ms following stimulus onset. DTI showed the SSD cohort to have extensive fractional anisotropy (FA) reduction in both auditory and non-auditory tracts and regions. Overlaying functional and structural changes revealed by the two imaging techniques demonstrated close registration of cortical areas and white matter tracts that expressed brain plasticity. Hence, complete loss of input from one ear in adulthood triggers both functional and structural alterations to dorsal temporal and frontal-parietal areas.

Keyword Spotting in Continuous Speech Using Spectral and Prosodic Information Fusion

Keyword spotting in a continuous speech is a challenging problem and has relevance in applications like audio indexing and music retrieval. In this work, the problem of keyword spotting is addressed by utilizing the complementary information present in spectral and prosodic features of the speech signal. A thorough analysis of the complementary information is performed on a large Hindi language database developed for this purpose. Phonetic and prosodic distribution analysis is performed toward this end, using canonical correlation and Student T-distance function. Motivated by these analyses, novel methods for spectral and prosodic information fusion that optimize a combined error function is proposed. The fusion methods are developed both at the feature and the model level. Improved syllable sequence prediction and keyword spotting performance are obtained using these methods when compared to conventional methods of keyword spotting. Additionally, in order to enable comparison with the state-of-the-art deep learning-based methods, a novel method for improved syllable sequence prediction using deep denoising autoencoders is proposed. The performance of the methods proposed in this work is evaluated for keyword spotting using a syllable sliding protocol over a large Hindi database. Reasonable performance improvements are noted from the experimental results on syllable sequence prediction, keyword spotting, and audio retrieval.

Word Segmentation for Burmese Based on Dual-Layer CRFs

Burmese is an isolated language, in which the syllable is the smallest unit. Syllable segmentation methods based on matching lead to performance subject to the syllable segmentation effect. This article proposes a word segmentation method with fusion conditions of double syllable features. It combines word segmentation and segmentation of syllables into one process, thus reducing the impact of errors on the syllable segmentation of Burmese. In the first layer of the conditional random fields (CRF) model, Burmese characters as atomic features are integrated into the Burma section of the Barkis Speech Paradigm (Backus normal form) features to realize the Burma syllable sequence tags. In the second layer of the CRFs model, with the syllable marked as input, it realizes the sequence markers through building a feature template with syllables as atomic features. The experimental results show that the proposed method has a better effect compared with the method based on the matching of syllables.

The neuroanatomy of speech sequencing at the syllable level.

Correctly ordering a sequence of speech sounds is a crucial aspect of speech production. Although studies have yielded a rich body of data on the neural substrates of visuomotor sequencing and sequence learning, research on brain regions and their functions involving speech sequence production hasn’t attracted much attention until recently. Previous functional MRI studies manipulating the complexity of sequences at the phonemic, syllabic, and suprasyllabic levels have revealed a network of motor-related cortical and sub-cortical speech regions. In this study, we directly compared human brain activity measured with functional MRI during processing of a sequence of syllables compared with the same syllables processed individually. Among a network of regions independently identified as being part of the sensorimotor circuits for speech production, only the left posterior inferior frontal gyrus (pars opercularis, lIFG), the supplementary motor area (SMA), and the left inferior parietal lobe (lIPL) responded more during the production of syllable sequences compared to producing the same syllables articulated one at a time.

The role of vowel parameters in defining lexical and subsidiary stress in Ukrainian

Abstract Recent work suggests that Ukrainian represents a typologically rare bidirectional stress system with internal lapses, i.e. sequences of unstressed syllables in the vicinity of primary stress (Łukaszewicz and Mołczanow 2018a, b). The system is more intricate than the hitherto known bidirectional systems (e.g. Polish), and thus interesting from the theoretical perspective, as it involves interaction between free lexical stress and secondary stresses. Lexical and subsidiary prominence in Ukrainian have been shown to be expressed acoustically in terms of increased duration of the whole syllable. This leaves open the question of the role of classic vowel parameters in shaping prominence effects in this language. The present study fills this gap by investigating vowel duration, intensity, and F0 as potential acoustic correlates of primary and secondary stress in Ukrainian. It focuses on words with primary stress on the fifth syllable. Such words are predicted to have secondary stress on the first and third syllables. The results point to statistically significant lengthening of vowels carrying lexical stress as well as of those in the initial syllable, but not in the third syllable. A possible explanation is that other parameters, e.g. consonant duration, may be crucial in the case of word-internal subsidiary stress in Ukrainian.

Optimality Theory, Language Typology, and Universalist Metrics

In Russom (2011), I defended a universalist hypothesis that the constituents of poetic form are abstracted from natural linguistic constituents: metrical positions from phonological constituents, usually syllables; metrical feet from morphological constituents, usually words; and metrical lines from syntactic constituents, usually sentences. An important corollary to this hypothesis is that norms for realization of a metrical constituent are based on norms for the corresponding linguistic constituent. Optimality Theory provides a universalist account of relevant linguistic norms and deals effectively with situations in which norms conflict, employing ranked violable rules. Language Typology provides a universalist account of relevant syntactic norms. In this paper I integrate these independently grounded methodologies and use them to explain the distribution of constituents within the line, identifying a variety of important facts that seem to have escaped previous notice. Universalist claims are tested against meters from each of the major language types: subject-verb-object (SVO), subject-object-verb (SOV) and verb-subject-object (VSO). My findings are incompatible with the claim that “lines are sequences of syllables, rather than of words or phrases” (Fabb, Halle 2008: 11).

Zebra finches are sensitive to combinations of temporally distributed features in a model of word recognition.

Discrimination between spoken words composed of overlapping elements, such as "captain" and "captive," relies on sensitivity to unique combinations of prefix and suffix elements that span a "uniqueness point" where the word candidates diverge. To model such combinatorial processing, adult female zebra finches were trained to discriminate between target and distractor syllable sequences that shared overlapping "contextual" prefixes and differed only in their "informative" suffixes. The transition from contextual to informative syllables thus created a uniqueness point analogous to that present between overlapping word candidates, where targets and distractors diverged. It was found that target recognition depended not only on informative syllables, but also on contextual syllables that were shared with distractors. Moreover, the influence of each syllable depended on proximity to the uniqueness point. Birds were then trained birds with targets and distractors that shared both prefix and suffix sequences and could only be discriminated by recognizing unique combinations of those sequences. Birds learned to robustly discriminate target and distractor combinations and maintained significant discrimination when the local transitions from prefix to suffix were disrupted. These findings indicate that birds, like humans, combine information across temporally distributed features, spanning contextual and informative elements, in recognizing and discriminating word-like stimuli.

Bayesian Semiparametric Mixed Effects Markov Models With Application to Vocalization Syntax

ABSTRACTStudying the neurological, genetic, and evolutionary basis of human vocal communication mechanisms using animal vocalization models is an important field of neuroscience. The datasets typically comprise structured sequences of syllables or “songs” produced by animals from different genotypes under different social contexts. It has been difficult to come up with sophisticated statistical methods that appropriately model animal vocal communication syntax. We address this need by developing a novel Bayesian semiparametric framework for inference in such datasets. Our approach is built on a novel class of mixed effects Markov transition models for the songs that accommodate exogenous influences of genotype and context as well as animal-specific heterogeneity. Crucial advantages of the proposed approach include its ability to provide insights into key scientific queries related to global and local influences of the exogenous predictors on the transition dynamics via automated tests of hypotheses. The methodology is illustrated using simulation experiments and the aforementioned motivating application in neuroscience. Supplementary materials for this article, including a standardized description of the materials available for reproducing the work, are available as an online supplement.

Inhibiting Basal Ganglia Regions Reduces Syllable Sequencing Errors in Parkinson's Disease: A Computer Simulation Study.

Background: Parkinson's disease affects many motor processes including speech. Besides drug treatment, deep brain stimulation (DBS) in the subthalamic nucleus (STN) and globus pallidus internus (GPi) has developed as an effective therapy.Goal: We present a neural model that simulates a syllable repetition task and evaluate its performance when varying the level of dopamine in the striatum, and the level of activity reduction in the STN or GPi.Method: The Neural Engineering Framework (NEF) is used to build a model of syllable sequencing through a cortico-basal ganglia-thalamus-cortex circuit. The model is able to simulate a failing substantia nigra pars compacta (SNc), as occurs in Parkinson's patients. We simulate syllable sequencing parameterized by (i) the tonic dopamine level in the striatum and (ii) average neural activity in STN or GPi.Results: With decreased dopamine levels, the model produces syllable sequencing errors in the form of skipping and swapping syllables, repeating the same syllable, breaking and restarting in the middle of a sequence, and cessation (“freezing”) of sequences. We also find that reducing (inhibiting) activity in either STN or GPi reduces the occurrence of syllable sequencing errors.Conclusion: The model predicts that inhibiting activity in STN or GPi can reduce syllable sequencing errors in Parkinson's patients. Since DBS also reduces syllable sequencing errors in Parkinson's patients, we therefore suggest that STN or GPi inhibition is one mechanism through which DBS reduces syllable sequencing errors in Parkinson's patients.

The Effects of Syllable Sequence Frequency on EFL Learners' Speech Recognition

The Effects of Syllable Sequence Frequency on EFL Learners' Speech Recognition

Sequential stream segregation based on spatial cues: Behavioral and neural measurements

Differences in simulated spatial cues in the horizontal plane have been shown to enhance both voluntary and obligatory stream segregation of sounds with realistic spectro-temporal variations, such as sequences of syllables. In this experiment, listeners were presented with sequences of speech tokens, each consisting of a fricative consonant and a voiced vowel. The CV tokens were concatenated into interleaved sequences that alternated in simulated spatial positions. The interleaved sequences lasted 1 min. The listeners had to press a button each time they heard a repeated token. In the selective attention task, the listeners were asked to attend only one of the two interleaved sequences; in the global attention task, the listeners had to perceive the interleaved sequences as single stream to detect a repetition between the sequences. Simultaneous EEG measurements were made. The behavioral results confirmed that listeners were able to either attend selectively or globally, depending on the task requirements. The EEG waveforms differed between the two tasks, despite identical physical stimuli, reflecting the difference between global and selective attention. Both behavioral and EEG results reflected the effects of increasing spatial separation in enhancing selective attention and making global attention to the sequences more difficult.

Application of automatic speech recognition (ASR) techniques for automatic speech assessment in people with aphasia

Application of automatic speech recognition (ASR) techniques for automatic speech assessment in people with aphasia

Children retain implicitly learned phonological sequences better than adults: a longitudinal study.

Whereas adults often rely on explicit memory, children appear to excel in implicit memory, which plays an important role in the acquisition of various cognitive skills, such as those involved in language. The current study aimed to test the assertion of an age-dependent shift in implicit versus explicit learning within a theoretical framework that explains the link between implicit sequence memory and word-form acquisition, using the Hebb repetition paradigm. We conducted a one-year, multiple-session longitudinal study in which we presented auditory sequences of syllables, co-presented with pictures of aliens, for immediate serial recall by a group of children (8-9 years) and by an adult group. The repetition of one Hebb sequence was explicitly announced, while the repetition of another Hebb sequence was unannounced and, therefore, implicit. Despite their overall inferior recall performance, the children showed better offline retention of the implicit Hebb sequence, compared with adults who showed a significant decrement across the delays. Adults had gained more explicit knowledge of the implicit sequence than children, but this could not explain the age-dependent decline in the delayed memory for it. There was no significant age-effect for delayed memory of the explicit Hebb sequence, with both age groups showing retention. Overall performance by adults was positively correlated with measures of post-learning awareness. Performance by children was positively correlated with vocabulary knowledge. We conclude that children outperform adults in the retention over time of implicitly learned phonological sequences that will gradually consolidate into novel word-forms. The findings are discussed in the light of maturational differences for implicit versus explicit memory systems that also play a role in language acquisition. A video abstract of this article can be viewed at: https://youtu.be/G5nOfJB72t4.

Auditory-motor coupling affects phonetic encoding

Recent studies have shown that moving in synchrony with auditory stimuli boosts attention allocation and verbal learning. Furthermore rhythmic tones are processed more efficiently than temporally random tones ('timing effect'), and this effect is increased when participants actively synchronize their motor performance with the rhythm of the tones, resulting in auditory-motor synchronization.Here, we investigated whether this applies also to sequences of linguistic stimuli (syllables). We compared temporally irregular syllable sequences with two temporally regular conditions where either the interval between syllable onsets (stimulus onset asynchrony, SOA) or the interval between the syllables’ vowel onsets was kept constant. Entrainment to the stimulus presentation frequency (1 Hz) and event-related potentials were assessed in 24 adults who were instructed to detect pre-defined deviant syllables while they either pedaled or sat still on a stationary exercise bike.We found larger 1 Hz entrainment and P300 amplitudes for the SOA presentation during motor activity. Furthermore, the magnitude of the P300 component correlated with the motor variability in the SOA condition and 1 Hz entrainment, while in turn 1 Hz entrainment correlated with auditory-motor synchronization performance. These findings demonstrate that acute auditory-motor coupling facilitates phonetic encoding.

Learning Biases Underlie “Universals” in Avian Vocal Sequencing

Biological predispositions in vocal learning have beenproposed to underlie commonalities in vocal sequences, including for speech and birdsong, but cultural propagation could also account for such commonalities [1-4]. Songbirds such as the zebra finch learn the sequencing of their acoustic elements ("syllables") during development [5-8]. Zebra finches are not constrained to learn a specific sequence of syllables, but significant consistencies in the positioning and sequencing of syllables have been observed between individuals within populations and between populations [8-10]. To reveal biological predispositions in vocal sequence learning, we individually tutored juvenile zebra finches with randomized and unbiased sequences of syllables and analyzed the extent to which birds produced common sequences. In support of biological predispositions, birds tutored with randomized sequences produced songs with striking similarities. Birds preferentially started and ended their song sequence with particular syllables, consistently positioned shorter and higher frequency syllables in the middle of their song, and sequenced their syllables such that pitch alternated across adjacent syllables. These patterns are reminiscent of those observed in normally tutored birds, suggesting that birds "creolize" aberrant sequence inputs to produce normal sequence outputs. Similar patterns were also observed for syllables that were not used for tutoring (i.e., unlearned syllables), suggesting that motor biases could contribute to sequence learning biases. Furthermore, zebra finches spontaneously produced acoustic patterns that are commonly observed in speech and music, suggesting that sensorimotor processes that are shared across a wide range of vertebrates could underlie these patterns in humans.