Linking speech errors and phonological grammars: Insights from Harmonic Grammar networks

PIPS: A Parallel Planning Model of Sentence Production

Subject-verb agreement errors are common in sentence production. Many studies have used experimental paradigms targeting the production of subject-verb agreement from a sentence preamble (The key to the cabinets) and eliciting verb errors (… *were shiny). Through reanalysis of previous data (50 experiments; 102,369 observations), we show that this paradigm also results in many errors in preamble repetition, particularly of local noun number (The key to the *cabinet). We explore the mechanisms of both errors in parallelism in producing syntax (PIPS), a model in the Gradient Symbolic Computation framework. PIPS models sentence production using a continuous-state stochastic dynamical system that optimizes grammatical constraints (shaped by previous experience) over vector representations of symbolic structures. At intermediate stages in the computation, grammatical constraints allow multiple competing parses to be partially activated, resulting in stable but transient conjunctive blend states. In the context of the preamble completion task, memory constraints reduce the strength of the target structure, allowing for co-activation of non-target parses where the local noun controls the verb (notional agreement and locally agreeing relative clauses) and non-target parses that include structural constituents with contrasting number specifications (e.g., plural instead of singular local noun). Simulations of the preamble completion task reveal that these partially activated non-target parses, as well the need to balance accurate encoding of lexical and syntactic aspects of the prompt, result in errors. In other words: Because sentence processing is embedded in a processor with finite memory and prior experience with production, interference from non-target production plans causes errors.

Complexity of articulation planning in apraxia of speech: The limits of phoneme-based approaches

This report presents evidence suggesting that the phoneme-based approach taken by Romani, Galuzzi, Guariglia, and Goslin (Comparing phoneme frequency, age of acquisition, and loss in aphasia: Implications for phonological universals. Cognitive Neuropsychology, this issue) falls short of capturing the complexity of articulation planning in patients with apraxia of speech. Empirical and modelling data are reported to demonstrate that the apraxic pathomechanism resides in the hierarchical architecture of phonological words rather than in the context-independent properties of phonemes. Because the factors determining complexity of articulation planning are interlaced between gestural, syllabic, and metrical levels, they cannot be captured by markedness rankings limited to any of these levels.

Phonological regularity, perceptual biases, and the role of phonotactics in speech error analysis

Speech errors involving manipulations of sounds tend to be phonologically regular in the sense that they obey the phonotactic rules of well-formed words. We review the empirical evidence for phonological regularity in prior research, including both categorical assessments of words and regularity at the granular level involving specific segments and contexts. Since the reporting of regularity is affected by human perceptual biases, we also document this regularity in a new data set of 2,228 sublexical errors that was collected using methods that are demonstrably less prone to bias. These facts validate the claim that sound errors are overwhelmingly regular, but the new evidence suggests speech errors admit more phonologically ill-formed words than previously thought. Detailed facts of the phonological structure of errors, including this revised standard, are then related to model assumptions in contemporary theories of phonological encoding. This article is categorized under: Linguistics > Linguistic Theory Linguistics > Computational Models of Language Psychology > Language.

Phonology without universal grammar

The question of identifying the properties of language that are specific human linguistic abilities, i.e., Universal Grammar, lies at the center of linguistic research. This paper argues for a largely Emergent Grammar in phonology, taking as the starting point that memory, categorization, attention to frequency, and the creation of symbolic systems are all nonlinguistic characteristics of the human mind. The articulation patterns of American English rhotics illustrate categorization and systems; the distribution of vowels in Bantu vowel harmony uses frequencies of particular sequences to argue against Universal Grammar and in favor of Emergent Grammar; prefix allomorphy in Esimbi illustrates the Emergent symbolic system integrating phonological and morphological generalizations. The Esimbi case has been treated as an example of phonological opacity in a Universal Grammar account; the Emergent analysis resolves the pattern without opacity concerns.

Training Pseudoword Reading in Acquired Dyslexia: A Phonological Complexity Approach

BACKGROUND

Individuals with acquired phonological dyslexia experience difficulty associating written letters with corresponding sounds, especially in pseudowords. Previous studies have shown that reading can be improved in these individuals by training letter-sound correspondence, practicing phonological skills, or using combined approaches. However, generalization to untrained items is typically limited.

AIMS

We investigated whether principles of phonological complexity can be applied to training letter-sound correspondence reading in acquired phonological dyslexia to improve generalization to untrained words. Based on previous work in other linguistic domains, we hypothesized that training phonologically "more complex" material (i.e., consonant clusters with small sonority differences) would result in generalization to phonologically "less complex" material (i.e., consonant clusters with larger sonority differences), but this generalization pattern would not be demonstrated when training the "less complex" material.

METHODS & PROCEDURES

We used a single-participant, multiple baseline design across participants and behaviors to examine phonological complexity as a training variable in five individuals. Based on participants' error data from a previous experiment, a "more complex" onset and a "less complex" onset were selected for training for each participant. Training order assignment was pseudo-randomized and counterbalanced across participants. Three participants were trained in the "more complex" condition and two in the "less complex" condition while tracking oral reading accuracy of both onsets.

OUTCOMES & RESULTS

As predicted, participants trained in the "more complex" condition demonstrated improved pseudoword reading of the trained cluster and generalization to pseudowords with the untrained, "simple" onset, but not vice versa.

CONCLUSIONS

These findings suggest phonological complexity can be used to improve generalization to untrained phonologically related words in acquired phonological dyslexia. These findings also provide preliminary support for using phonological complexity theory as a tool for designing more effective and efficient reading treatments for acquired dyslexia.

Rules from words: a dynamic neural basis for a lawful linguistic process

Listeners show a reliable bias towards interpreting speech sounds in a way that conforms to linguistic restrictions (phonotactic constraints) on the permissible patterning of speech sounds in a language. This perceptual bias may enforce and strengthen the systematicity that is the hallmark of phonological representation. Using Granger causality analysis of magnetic resonance imaging (MRI)-constrained magnetoencephalography (MEG) and electroencephalography (EEG) data, we tested the differential predictions of rule-based, frequency-based, and top-down lexical influence-driven explanations of processes that produce phonotactic biases in phoneme categorization. Consistent with the top-down lexical influence account, brain regions associated with the representation of words had a stronger influence on acoustic-phonetic regions in trials that led to the identification of phonotactically legal (versus illegal) word-initial consonant clusters. Regions associated with the application of linguistic rules had no such effect. Similarly, high frequency phoneme clusters failed to produce stronger feedforward influences by acoustic-phonetic regions on areas associated with higher linguistic representation. These results suggest that top-down lexical influences contribute to the systematicity of phonological representation.

On the nature of sonority in spoken word production: evidence from neuropsychology

The concept of sonority - that speech sounds can be placed along a universal sonority scale that affects syllable structure - has proved valuable in accounting for a wide spectrum of linguistic phenomena and psycholinguistic findings. Yet, despite the success of this concept in specifying principles governing sound structure, several questions remain about sonority. One issue that needs clarification concerns its locus in the processes involved in spoken language production, and specifically whether sonority affects the computation of abstract word form representations (phonology), the encoding of context-specific features (phonetics), or both of these processes. This issue was examined in the present study investigating two brain-damaged individuals with impairment arising primarily from deficits affecting phonological and phonetic processes, respectively. Clear effects of sonority on production accuracy were observed in both individuals testing word onsets and codas in word production. These findings indicate that the underlying principles governing sound structure that are captured by the notion of sonority play a role at both phonological and phonetic levels of processing. Furthermore, aspects of the errors recorded from our participants revealed features of syllabic structure proposed under current phonological theories (e.g., articulatory phonology).

Apraxia of speech: concepts and controversies

PURPOSE

This article was written as an editorial to a collection of original articles on apraxia of speech (AOS) in which some of the more recent advancements in the understanding of this syndrome are discussed. It covers controversial issues concerning the theoretical foundations of AOS. Our approach was motivated by a change of perspective on motor speech that has taken place in neurobiology, neurolinguistics, phonology, and phonetics during the past few decades.

METHOD

The literature on AOS is reviewed from 3 different but overlapping perspectives-that is, a disconnection, a motor memory, and a fine motor skill perspective. Separate sections are devoted to the delimitations of AOS from oral facial apraxia, dysarthria, and phonological impairment.

CONCLUSIONS

We conclude that many of the still unresolved conceptual issues about AOS arise from an underspecification of existing models of spoken language production. We suggest that phonological and motor impairments of sound production should be studied by an integrated approach.

The emergence of an unmarkedness effect in Mandarin speech errors: nasals in a coda position

This study aims to explore how the markedness effect shapes Mandarin slips of the tongue with respect to nasals in syllable-final positions. Data were collected via natural speech and elicitation tasks from 35 participants' reading of 346 test items. Three hundred and eight slips in Mandarin from natural data and 360 slips from elicited data were investigated. This study shows that there exists a strong preference for unmarked coronal nasals over marked dorsal nasals in the syllable-final position in both spontaneous and elicited Mandarin slips. This tendency toward the unmarked [n] reveals that the influence of the unmarkedness effect is present in the coda position in Mandarin slips. Interestingly, this tendency is inconsistent with that found in a previous study by Wan of Mandarin slips in the onset position, which shows a tendency for coronals to be replaced by other sounds. This suggests an onset-coda distinction occurring in Mandarin speech errors, which implies that the markedness effect works differently in distinct syllable positions. More precisely, the unmarkedness effect emerges in the coda position in Mandarin slips, leading to the occurrence of unmarked segments, whereas it submerges in the onset position, resulting in marked segments.