Velar Fronting Research Articles

Speech Perception and Phonological Representation in 5 to 6 Year-Old Typically Developing Children

Objectives: This study aimed to examine the development of speech perception and phonological representation in typically developing children aged 5-6 years. It also explored the relationship between receptive vocabulary, consonant accuracy, nonword repetition performance, and speech perception and phonological representation. Methods: The study involved 77 typically developing children aged 5-6 years. The speech perception identification tasks included minimal pairs that reflected developmental error patterns. The phonological representation judgment tasks involved manipulating consonants and vowels, as well as the number of distinctive features, to examine performance differences under various speech sound manipulation conditions. Results: Performance on both speech perception and phonological representation tasks significantly increased with age. There were also significant differences in performance based on speech sound manipulation conditions. Specifically, in the speech perception task, performance was significantly higher when items focused on the stopping of fricatives rather than the fronting of velars. In the phonological representation task, performance was significantly better in vowel manipulation compared to consonant manipulation, and with two distinctive feature manipulations compared to one. Speech perception tasks showed a significant correlation only with receptive vocabulary, whereas phonological representation tasks showed significant positive correlations with receptive vocabulary, consonant accuracy, and nonword repetition performance. Conclusion: The study confirms that speech perception and phonological representation are developing between ages 5 and 6 in typically developing children. It also suggests that speech perception and phonological representation develop through a complex interplay with speech production abilities and receptive vocabulary.

Analyzing the Speech Sound Structures of Indonesian Child Language

In the acquisition of language, there could be gradual construction and systematic development of the children's linguistic skills. In their communication, the children speak the words, but their sounds may not be as complete as the adults. This difference between the child and adult language has attracted the attention of scholars in language acquisition to examine if there are specific structures of the child language. This research focuses on the structures of the child's speech sound to see what aspects could explain the difference between child and adult language. The data were the speech of 37 children (Male = 20; Female = 17) with the age range of 1;2 (one year two months) to 5;2 (five years two months). The data was transcribed, and its phonological aspects were classified. PRAAT software (version 6.2.02) was used to study the phonetic properties that support the explanation of the phonological aspects, especially for intensity, duration, and pitch. The study revealed some important aspects of the child language, i.e., syllable deletion, nasal assimilation, velar fronting, lateral substitution, vowel lowering and raising, and pitch harmony. This study may shed new light on the research of speech sound structure for promoting children's literacy programs in Indonesia.

The Dorsal Differentiation of Velar From Alveolar Stops in Typically Developing Children and Children With Persistent Velar Fronting.

Purpose This study has two key aims: first, to provide developmental articulatory norms for the alveolar-velar distinction in 30 English-speaking typically developing (TD) children; second, to illustrate the utility of the reported measures for classifying and quantifying the speech of children with a history of persistent velar fronting as they develop the contrast longitudinally. Method This study involved secondary data analysis of the UltraSuite corpus comprising ultrasound tongue imaging recordings of speech materials from 30 typical children and longitudinal data from five children with persistent velar fronting undergoing ultrasound visual biofeedback intervention. We present two new measures of coronal dorsal differentiation: KTMax and KT crescent area. These measures distinguish /k/ and /t/ by quantifying the magnitude of this distinction in absolute spatial terms (mm of linear dorsal difference). For the typical children, we report these measures in corner vowel contexts. We then compare these to dorsal productions by the children with speech disorders, before, during, and after intervention. Results Both measures reliably distinguished /k/ and /t/ in TD children. There was an effect of vowel, with larger KTmax and KT crescent area in /a/ and /o/ vowel contexts than in an /i/ context. The children with persistent velar fronting showed KTmax values near zero before intervention, showing a complete merger between /k/ and /t/. During intervention, they showed variable KTmax values. Post intervention, they showed values within the range of typical children. Conclusions This study provides articulatory norms derived from ultrasound tongue imaging for the dorsal differentiation in alveolar and velar stops in TD children. By applying these norms to children with persistent velar fronting as they acquire this contrast, we see that /k/ is acquired in an articulatorily gradient manner.

Exploiting ultrasound tongue imaging for the automatic detection of speech articulation errors

Speech sound disorders are a common communication impairment in childhood. Because speech disorders can negatively affect the lives and the development of children, clinical intervention is often recommended. To help with diagnosis and treatment, clinicians use instrumented methods such as spectrograms or ultrasound tongue imaging to analyse speech articulations. Analysis with these methods can be laborious for clinicians, therefore there is growing interest in its automation. In this paper, we investigate the contribution of ultrasound tongue imaging for the automatic detection of speech articulation errors. Our systems are trained on typically developing child speech and augmented with a database of adult speech using audio and ultrasound. Evaluation on typically developing speech indicates that pre-training on adult speech and jointly using ultrasound and audio gives the best results with an accuracy of 86.9%. To evaluate on disordered speech, we collect pronunciation scores from experienced speech and language therapists, focusing on cases of velar fronting and gliding of /r/. The scores show good inter-annotator agreement for velar fronting, but not for gliding errors. For automatic velar fronting error detection, the best results are obtained when jointly using ultrasound and audio. The best system correctly detects 86.6% of the errors identified by experienced clinicians. Out of all the segments identified as errors by the best system, 73.2% match errors identified by clinicians. Results on automatic gliding detection are harder to interpret due to poor inter-annotator agreement, but appear promising. Overall findings suggest that automatic detection of speech articulation errors has potential to be integrated into ultrasound intervention software for automatically quantifying progress during speech therapy.

Phonological Patterns in Ukwuani Children of Three to Five Years Old

This article is a study of the phonological patterns in child language development. Using data from Ukwuani children of three to five years old, we identify those patterns that are prevalent in normal child development for the purpose of assessing and identifying children with phonological disorders. Using the Ibadan 400 wordlist, a predetermined wordlist of 400 items, we identified patterns such as: stopping, deaffrication, velar fronting, liquid gliding, nasal assimilation and labial assimilation. We note that children make some deviations in an attempt to produce the adult form of the language and that these deviations may not be cases of disorders but simply simplification processes. However, if they hold on to these patterns beyond a certain age, it results in developmental phonological disorder. The paper thus recommends that child’s phonological patterns be assessed using the phonological milestones or universal patterns that underlie the speech forms of infants at a certain age so as to identify children who after the recommended age still present constraints in trying to produce the adult form. This will help in early intervention in the case of such a disorder.

Enabling New Articulatory Gestures in Children With Persistent Speech Sound Disorders Using Ultrasound Visual Biofeedback.

Purpose This study evaluated ultrasound visual biofeedback treatment for teaching new articulations to children with a wide variety of speech sound disorders. It was hypothesized that motor-based intervention incorporating ultrasound would lead to rapid acquisition of a range of target lingual gestures with generalization to untreated words. Method Twenty children aged 6-15 years with a range of mild to severe speech disorders affecting a variety of lingual targets enrolled in a case series with replication. Of these, 15 children completed the intervention. All of the children presented with a variety of errors. We therefore employed a target selection strategy to treat the most frequent lingual error. These individual speech targets were treated using ultrasound visual biofeedback as part of ten to twelve 1-hr intervention sessions. The primary outcome measure was percentage of target segments correct in untreated wordlists. Results Six children were treated for velar fronting; 3 children, for postalveolar fronting; 2 children, for backing alveolars to pharyngeal or glottal place; 1 child, for debuccalization (production of all onsets as [h]); 1 child, for vowel merger; and 2 children, for lateralized sibilants. Ten achieved the new articulation in the 1st or 2nd session of intervention, despite no children being readily stimulable for their target articulation before intervention. In terms of generalization, effect sizes for percentage of target segments correct ranged from no effect (5 children), small effect (1 child), medium effect (4 children), and large effect (5 children). Conclusions Ultrasound visual biofeedback can be used to treat a wide range of lingual errors in children with various speech sound disorders, from mild to severe. Visual feedback may be useful for establishing new articulations; however, generalization is more variable.

Covert contrast and covert errors in persistent velar fronting

ABSTRACTAcoustic and articulatory studies demonstrate covert contrast in perceptually neutralised phonemic contrasts in both typical children and children with speech disorders. These covert contrasts are thought to be relatively common and symptomatic of phonetic speech disorders. However, clinicians in the speech therapy clinic have had no easy way of identifying this covertness. This study uses ultrasound tongue imaging to compare tongue contours for /t/and /k/in seven children with persistent velar fronting. We present a method of overlaying tongue contours to identify covert contrast at the articulatory level. Results show that all seven children, contrary to expectations, produced both /t/and /k/with near-identical tongue shapes showing no evidence of covert contrast. However, further analysis of one of the participants showed highly variable tongue shapes for /t/and /k/, including retroflex productions of both. Although not phonologically conditioned, this covert error is evidence of speech disorder at the phonetic level.

Velar–vowel coarticulation in a virtual target model of stop production

Velar–vowel coarticulation in English, resulting in so-called velar fronting in front vowel contexts, was studied using ultrasound imaging of the tongue during /k/ onsets of monosyllabic words with no coda or a labial coda. Ten native English speakers were recorded and analyzed. A variety of coarticulation patterns that often appear to contain small differences in typical closure location for similar vowels was found. An account of the coarticulation pattern is provided using a virtual target model of stop consonant production where there are two /k/ allophones in English, one for front vowels and one for non-front vowels. Small differences in closure location along the palate between productions within each context are the result of the trajectory of movement of the tongue from the vowel to vowel through the virtual target beyond the limit of the palate. The overall pattern is thus seen as a combination of a large planned allophonic difference between consonant closure targets and smaller phonetic differences for each particular vowel quality that are the result of coarticulation.

Using ultrasound visual feedback to remediate velar fronting in preschool children: A pilot study

ABSTRACTAnecdotally, velar fronting can be difficult to remediate in some children. This pilot study examined the use of ultrasound visual feedback in remediating velar fronting in typically developing children. A single-case, multiple-baseline across-subjects experimental design was used to examine acquisition, retention and generalisation of velar treatment targets. Two otherwise typically developing children (P1, aged 4;0; P3, aged 4;11) completed the study. The productions of /k/ and /ɡ/ at syllable level were targeted during treatment. P1 improved her productions of /k/ and /ɡ/ at syllable level during the treatment period and achieved correct production at word level during follow-up. P3 made no improvements in his productions of velar targets. This study suggests that ultrasound visual feedback may be an option for remediating velar fronting in some preschoolers. Further study is required.

Covert contrast in velar fronting: An acoustic and ultrasound study

ABSTRACTThere is growing evidence that speech sound acquisition is a gradual process, with instrumental measures frequently revealing covert contrast in errors perceived to involve phonemic substitution. Ultrasound imaging has the potential to expand our understanding of covert contrast by showing whether a child uses different tongue shapes while producing sounds that are perceived as neutralised. This study used an ultrasound measure (Dorsum Excursion Index) and acoustic measures (VOT and spectral moments of the burst) to investigate overt and covert contrast between velar and alveolar stops in child speech. Participants were two children who produced a perceptually overt velar-alveolar contrast and two children who neutralised the contrast via velar fronting. Both acoustic and ultrasound measures revealed significant differences between perceptually distinct velar and alveolar targets. One child with velar fronting demonstrated covert contrast in one acoustic and one ultrasound measure; the other showed no evidence of contrast. Clinical implications are discussed in this article.

Using ultrasound articulatory signals to investigate the phonetic motivations of English /æ/ tensing

A common simplifying technique in ultrasound studies of variation is to select a single representative frame for each token, sacrificing dynamic information that is often critical for understanding the phonetic motivations of phonological phenomena. We examine the phonetic motivations for tongue body raising in English /æ/ tensing (e.g., Labov et al. 2005) in 23 North American English speakers using phonetically meaningful time-varying articulatory signals extracted directly from ultrasound video. An articulatory measure of /æ/ tenseness is generated using regression to find the linear combination of articulatory principal components (found using EigenTongue Feature Extraction; Hueber et al. 2007) that best accounts for the F2-F1 difference in front vowels. We have previously shown (Carignan et al. 2015) that tensing before /m n/ involves tongue body raising that is timed to the vowel nucleus, whereas tensing before /ɡ ŋ/ involves anticipating the velar closure to different degrees in different dialects. Here, we examine the phonetic motivations for this /æ/ tensing. An articulatory measure of velar fronting shows increased /ɡ/ fronting in speakers who tense /æ/ before /ɡ/, and a purely lingual analog of F1 shows that the effect of nasalization on F1 is much smaller than the phonological effect of pre-nasal /æ/ tensing.

Acquisition of velars: A whole-word approach

This study focuses on the acquisition of velars in a child, Max, aged 1;09–4;08, with protracted phonological development, possibly as a result of his diverse input conditions: he is an internationally adopted child who produces his first words shortly after exposure to English at 1;09. Max’s acquisition of velars is characterised by U-shaped development as well as by a positional velar-fronting process, in which velars are realised consistently in prosodically-weak but inconsistently in prosodically-strong positions. In prosodically-strong positions, they are conditioned by vowel quality, voicing, the place-of-articulation of the post-vocalic consonant and whether they are part of an obstruent–sonorant cluster. The study aims to account for Max’s U-shaped pattern of development, his positional velar fronting process and his partial realisation of prosodically-strong velars appealing to generative and usage-based approaches of phonological development.

Using PhonBank and Phon in studies of phonological development and disorders

The goal of this paper is to present an overview of new tools that can be used to further our understanding of phonological development and disorders. We begin with a summary of the field of child phonology with a focus on databases and methods of analysis and then move to a description of PhonBank, a shared database for the study of phonology, and Phon, a specialised software system capable of performing various types of phonological analyses based on both phonetic transcriptions and acoustic analyses of speech productions. We provide a detailed example of using PhonBank and Phon to examine the use of velar fronting using longitudinal data from one child with typical development and three children with phonological disorder. We conclude with an emphasis on data sharing and its central relevance to further advances in our field.

Phonologial Development in Bangla: A Normative Study.

This study investigates the various phonological processes operational in the speech of 90 native Bangla spoken children between the age of 3;0 – 3;11 years. The speech of all children was recorded during the administration of the developed word list and was transcribed for analysis. Equality of proportions was used to investigate the observed pattern of variation in speech. Overall this study has established two aspects of speech development: age at which the error patterns were suppressed and the percentage of children exhibiting the obtained phonological processes. Processes like medial consonant deletion, unstressed syllable deletion, /l/ deletion, vowel unrounding, alveolar fronting, denasalization, stopping (except stopping of affricates and fricatives), palatalization and monothongization were eliminated by 3 years 5 months, while nasalization, backing of stops, initial consonant deletion, and coalescence were not found in age beyond 3 years and 9 months. Processes like vowel rising, nasalization, stopping, nasal assimilation, stop assimilation, velar fronting, and deaffrication decreased significantly as the chronological age progressed from 3 to 4 years. Other processes like cluster reduction, epenthesis, final consonant deletion, deaspiration, /r/ deletion, affrication (of fricatives), liquid replacement, and fronting of retroflex were considered to persist beyond 4 years of age. The results however refute the fact that, the mastery of phonological system is completed by 4 years of age. Native Bangla speaking children continues to use simplification for clusters, final consonants, fricatives, liquids, retroflex sounds, and the aspirated counterparts of stops, even after the age of four. The results thus provide a profile of the underlying rules a typically developing child uses, which can be served as a basis for planning remediation. Also information about typical errors helps to delineate the normal course of acquisition; consequently, a child’s atypical phonologic development can be evaluated against normal or typical error patterns.

An analysis of velar fronting in child phonology based on a longitudinal corpus study

Velar fronting is a well-known phenomenon in child phonology where velars in prosodically strong position are produced as coronals, due to child’s articulatory limitations. Velar fronting is one of the unnatural phonological processes that are observed only in child, not in any known adult system. Velar fronting in one child is closely investigated through a longitudinal study using the CHILDES corpus. It turns out that the acquisition of velar production is achieved during a period of four months, yielding an S-shaped developmental curve. The result of the longitudinal study supports a view that in phonological acquisition, constraint demotion does not take place immediately but gradually as the Gradual Learning Algorithm (GLA) predicts. Assuming that velar fronting arises from the gap between perception and production in child, an Optimality-Theoretic analysis is provided, based on the framework in Pater (2004). Finally, a learning simulation is conducted using the GLA with the proposed constraint schema, fed by the real-life corpus data. The results show how ranking values of relevant constraints change over time in a child.

Positional velar fronting: An updated articulatory account

This study develops the hypothesis that the child-specific phenomenon of positional velar fronting can be modeled as the product of phonologically encoded articulatory limitations unique to immature speakers. Children have difficulty executing discrete tongue movements, preferring to move the tongue and jaw as a single unit. This predisposes the child to produce undifferentiated linguopalatal contact, neutralizing the coronal-velar contrast. Adopting a phonetically sensitive model of phonology, I propose that children's difficulty with discrete tongue movement can be encoded in a violable constraint, Move.as-Unit. The positional nature of fronting reflects the fact that discrete lingual movement is penalized more heavily in the motorically challenging context of a larger gesture. This analysis is supported with a longitudinal study of one child (3 ; 9 to 4 ; 4) whose fronting was conditioned by both segmental and prosodic factors. Adopting Move.as-Unit in a Harmonic Grammar framework makes it possible to reframe disparate-seeming conditioning factors as a unified grammatical system.

Child Consonant Harmony: Identification and Properties

The study investigates the status of Consonant Harmony in the process of language acquisition, based on longitudinal data of two typically developing children acquiring Hebrew. The analysis indicates that Consonant Harmony is motivated mainly by prosodic factors; the directionality of assimilation between identical positions (e.g. onset-onset) is usually correlated with the direction of prosodic development—from old to new (i.e. from right to left). In addition, segmental (or phonotactic) factors may also play a role—for one child Consonant Harmony is used mainly to reduce the sonority of the target. On the other hand, the analysis does not support previous claims that Consonant Harmony involving place of articulation is governed by a markedness trigger-target hierarchy. I propose that a trigger-target hierarchy (if such exists) depends much on input frequency and individual factors.In addition to examining the motivation behind Consonant Harmony, I propose in this study a statistically based method to separate unambiguous Consonant Harmony from potential context-free substitutions (e.g. velar fronting). With this method, I show that a large part of the harmonized words produced by the children can be attributed to context-free substitutions, and thus suggest that Consonant Harmony may not be as common as previously assumed.The findings of the present study are affected to some extent by inter-subject variation. The two children exhibited differences both in the use of Consonant Harmony (abundance, duration, etc.) and in general language development (segmental, prosodic and lexical). These findings, other than being indicative of individuality in language acquisition, limit the extent to which general conclusions can be made.

Identification of phonological processes in preschool children's single-word productions

Speech and language therapists often refer to phonological data norms as part of their assessment protocols in evaluating the communication skills of the preschool child. There is a variety of norms available, and although broadly similar, differences are embedded within their definitions of mastery of the adult target system. To compare phonological processes present in the single-word productions of 94 West of Scotland preschool children with published normative data relating to typical ages of elimination of phonological processes. The 94 children, grouped into four 6-month age bands from 3.1 to 4.11 years, named 78 pictures. Their responses were broadly transcribed and then analysed for phonological processes. The presence of velar fronting, stopping of affricates and [s] cluster reduction in the data set was found to mirror previous research. However, there was a lower-than-expected incidence by age groups of palato-alveolar fronting, stopping of fricatives and obstruent cluster reduction. Speech and language therapists frequently rely on phonological normative data as part of their assessment and management of children with speech delay. Evidence from children recruited from typical mainstream nursery classes indicates that there are distinct differences between what would be expected of them with reference to normative data for some phonological processes and what they produce. UK clinical guidelines recommend the consideration of both the acquisition of phonemes and the presence of phonological processes when assessing and planning intervention. However, differences in development and occurrence within processes in relation to phonological development may have implications for clinicians' decision-making. Further research is proposed in relation to the extent to which phonological norms contribute to such clinical decision-making.

On the interaction of velar fronting and labial harmony

This article documents the typological occurrence and interactions of two seemingly independent error patterns, namely Velar Fronting and Labial Harmony, in a cross-sectional investigation of the sound systems of 235 children with phonological delays (ages 3;0 to 7;9). The results revealed that the occurrence of Labial Harmony depends on the occurrence of Velar Fronting, and that, when these processes co-occurred, all three predicted types of interactions were attested. A constrained version of Optimality Theory is put forward that offers a unified explanation for the implicational relationship between these error patterns and their observed interactions. The findings are compared with the results from other studies and are considered for their theoretical and clinical implications.

Spanish-English Articulation and Phonology of 4- and 5-Year-Old Preschool Children

In this study, it was postulated that typically developing (i.e., normally developing without incidence of a speech or language delay or disorder) Spanish/Englishspeaking children ages 4 to 5 years old would show different articulation productions and phonological patterns in both languages. Sixteen participants from Florida were tested with Spanish and English articulation and phonology tests. For articulation, two manner or articulation comparisons were found to be significant (i.e., plosives and liquids/glides). In addition, two phonological patterns (i.e., stopping and velar fronting) were significantly different. Normative articulation and phonological Spanish and English data were obtained and should be useful for today’s public school speech-language pathologists. Further research should include normative data for bilingual children with articulation and/or phonological disorders to develop more appropriate treatments. In addition, it is recommended that other languages be investigated as the nation is also experiencing growth in languages beyond Spanish.