Natural domains of cyclicity in phonological acquisition

Complexity and cross-linguistic transfer in intervention for Spanish–English bilingual children with speech sound disorder

With bilingual children, intervention for speech sound disorders must consider both of the child’s phonological systems, which are known to interact with each other in development. Further, cross-linguistic generalization following intervention for bilingual children with speech sound disorders (i.e. the impact of treatment in one language on the other) has been documented to varying degrees in some prior studies. However, none to date have documented the cross-linguistic impact of treatment with complex targets (e.g. consonant clusters) for bilingual children. Because complex phonological targets have been shown to induce system-wide generalization within a single language, the potential for bilingual children to generalize learning across languages could impact the efficiency of intervention in this population. This pilot intervention study examines the system-wide, cross-linguistic effects of treatment targeting consonant clusters in Spanish for two Spanish–English bilingual children with phonological disorder. Treatment was provided with 40-minute sessions in Spanish via teletherapy, three times per week for six weeks. Comprehensive phonological probes were administered in English and Spanish prior to intervention and across multiple baselines. Pre-intervention data were compared to data from probes administered during and after intervention to generate qualitative and quantitative measures of treatment outcomes and cross-linguistic generalization. Results indicate a medium effect size for system-wide generalization in Spanish (the language of treatment) and English (not targeted in treatment), for both participants (mean effect size in Spanish: 3.6; English 4.3). These findings have implications for across-language transfer and system-wide generalization in treatment for bilingual children. 

Automated phonological analysis and treatment target selection using AutoPATT

Automated analyses of speech samples can offer improved accuracy and timesaving advantages that streamline clinical assessment for children with a suspected speech sound disorder. In this paper, we introduce AutoPATT, an automated tool for clinical analysis of speech samples. This free, open-source tool was developed as a plug-in for Phon and follows the procedures of the Phonological Analysis and Treatment Target Selection protocol, including extraction of a phonetic inventory, phonemic inventory with corresponding minimal pairs, and initial consonant cluster inventory. AutoPATT also provides suggestions for complex treatment targets using evidence-based guidelines. Automated analyses and target suggestions were compared to manual analyses of 25 speech samples from children with phonological disorder. Results indicate that AutoPATT inventory analyses are more accurate than manual analyses. However, treatment targets generated by AutoPATT should be viewed as suggestions and not used to substitute necessary clinical judgement in the target selection process.

Phonological complexity in intervention for Spanish-speaking children with speech sound disorder

The efficiency of intervention for children with speech sound disorder may be influenced by linguistic complexity of the phonological intervention target. Complex targets, particularly, later-acquired, less-known consonants and consonant clusters, have been linked to greater post-intervention generalization to untargeted phonological structures. Yet there is little direct evidence to support target selection based on linguistic complexity for Spanish-speaking children with speech sound disorder. This intervention study utilizes an experimental single-case design to examine the efficacy of intervention in Spanish using different complex targets (i.e. /ɡɾ/, /bɾ/, and /l/). For each of the four Spanish-speaking children with speech sound disorder, sounds at 0% accuracy during baseline were monitored across the baseline period, during and post-intervention, and at one- and two-month follow-up visits. Over the course of intervention, only one participant achieved mastery of the targeted structure in practiced words. However, all participants demonstrated some amount of broad phonological generalization to untargeted consonants or clusters. Variable learning trajectories and broad phonological generalization are discussed as they relate to participant characteristics and linguistic complexity.

A qualitative exploration of speech-language pathologists' intervention and intensity provision for children with phonological impairment

PURPOSE

The aim of this study was to explore the reasons behind speech-language pathologists' (SLPs') current clinical practices (intervention and intensity provision) for children (0-18 years) with phonological impairment.

METHOD

Three focus groups each with five SLPs and six 1:1 interviews with SLP managers from one region of the UK (n = 21) were carried out. A thematic analysis was undertaken.

RESULT

SLPs often used an eclectic mix of familiar approaches with easily-accessible therapy materials. SLPs only reported deviating from their core approach if the child did not progress in therapy. Mixed responses were gathered on the perceived feasibility of transferring evidence-based intervention intensities into clinical practice. The importance of parents to increase intensity provision at home was noted. Barriers to SLPs' evidence-based decision-making included: time; confidence levels; service-related restrictions and; difficulty replicating research in practice. Having peer support and access to decision-making pathways and manualised intervention protocols were considered ways to overcome these barriers.

CONCLUSION

There is a research-practice gap in which SLPs' current practices are driven by organisational factors, their own preferences and child-specific factors. To narrow this gap, SLPs suggested the development of time-saving, evidence-based tools.

A motor learning perspective for optimizing intervention intensity

Baker (2012) has addressed the critical issue of optimizing intervention intensity in the field of speech-language pathology. While this provides a useful framework from which to examine treatment intensities across a variety of approaches, it does little to inform how certain factors (e.g., feedback frequency, practice schedules) might be manipulated to optimize learning in ways that are effective and efficient. Evidence from the speech and non-speech motor learning literature suggests that the optimal intensities for utilizing practice and feedback are dependent on interactive factors such as task variability, target complexity, and therapeutic goals. In light of the complex interactions of treatment factors, it is proposed that the principles of motor learning be used as a guide to develop precise, interactive models that describe the optimal treatment conditions for specific approaches to intervention in speech-language pathology.

Evidence-Based Practice for Children With Speech Sound Disorders: Part 1 Narrative Review

Purpose

This article provides a comprehensive narrative review of intervention studies for children with speech sound disorders (SSD). Its companion paper (Baker & McLeod, 2011) provides a tutorial and clinical example of how speech-language pathologists (SLPs) can engage in evidence-based practice (EBP) for this clinical population.

Method

Studies reporting speech sound intervention for children with SSDs published from 1979 to 2009 were identified and coded.

Results

One hundred thirty-four intervention studies were identified. Intervention typically was conducted by an SLP in a one-to-one individual format for 30- to 60-min sessions 2 to 3 times per week. Total duration of intervention (from assessment to discharge) was reported for 10 studies and ranged from 3 to 46 months. Most studies were either Level IIb (quasi-experimental studies, 41.5%) or Level III (nonexperimental case studies, 32.6%). Single-case experimental design (29.6%) was the most frequently used experimental research design. There were 7 distinct approaches to target selection and 46 distinct intervention approaches, with 23 described in more than 1 publication. Each approach was associated with varying quantities and levels of evidence, according to research design.

Conclusion

Collaborative research reflecting higher levels of evidence using rigorous experimental designs is needed to compare the relative benefits of different intervention approaches.

An analysis of the sonority hypothesis and cluster realization in a child with phonological disorder

This study describes the realization of onset and coda clusters in a 4-year old child acquiring American English, and with a higher than usual level of unintelligible speech. It reviews previous studies that have tested cluster realization against markedness and, in particular, the sonority hypothesis. This latter predicts steep rises in sonority at onsets and more gradual falls in sonority at codas of syllables. The data collected for this study cover four different onset cluster types and three different coda cluster types, and are derived from spontaneous speech produced during clinical sessions. An analysis of the patterns of cluster realizations shows that the participant's cluster realizations do not always follow the sonority hypothesis, and various factors are discussed that could be motivating the child's choice of realization.

Typically developing and speech-impaired children's adherence to the sonority hypothesis

During phonological development, children frequently produce consonant clusters as consonant singletons, a process commonly referred to as cluster reduction. The principles of sonority may provide a theoretical basis for explaining patterns of cluster reduction evident in children's speech. Two studies were conducted to investigate whether children's word-initial cluster reductions adhered to the sonority hypothesis. Study one involved 16 children with typically developing speech, and study two involved 40 children with impaired speech. The children's consonant cluster productions characterized by a cluster reduction were analysed. When both groups of participants reduced word-initial clusters to a target consonant, the sonority hypothesis was adhered to; but when the clusters were reduced to a non-target consonant, the sonority hypothesis was violated. Analysis of target and non-target reductions revealed that some reductions of the individual clusters, and those within specific cluster categories, adhered to the sonority hypothesis while others did not. In light of these findings, it is suggested that although sonority is a valuable concept, it may not account for all patterns of cluster reduction evident in children's speech.

Consonant cluster development in two-year-olds: general trends and individual difference

A holistic view of phonological development can be attained only through exploration of the relationship between universal developmental sequences, to establish a general pattern of development and individual learning and to provide information regarding variability. This study examined consonant cluster production, looking specifically at the relationship between general trends and individual differences as children acquire these sounds. The spontaneous speech of 16 normally developing Anglo-Australian 2-year-olds was elicited monthly for 6 months, and the corpus of 96 samples was examined using independent and relational phonological analyses. Data demonstrated that 2-year-olds were able to produce a range of consonant clusters in word-initial and word-final position, but few of the younger participants could produce consonant clusters correctly. Only half of the participants showed an increase in the percent of consonant clusters produced correctly over the 6-month period; however, their developing phonological maturity was revealed in the increase in the range and diversity of their repertoire of consonant clusters and by their closer approximations to the adult target. Specific findings of the study were compared to 10 trends for children's acquisition of consonant clusters emerging from the literature over the last 70 years.

Syllable onsets II: three-element clusters in phonological treatment

This study extends the application of the Sonority Sequencing Principle, as reported in J. A. Gierut (1999), to acquisition of word-initial 3-element clusters by children with functional phonological delays (ages in years;months: 3;4 to 6;3). The representational structure of 3-element clusters is complex and unusual because it consists of an s-adjunct plus a branching onset, which respectively violate and conform to the Sonority Sequencing Principle. Given the representational asymmetry, it is unclear how children might learn these clusters in treatment or whether such treatment may even be effective. Results of a single-subject staggered multiple-baseline experiment demonstrated that children learned the treated 3-element cluster in treatment but showed no further generalization to similar types of (asymmetric) onsets. Treatment of 3-element clusters did, however, result in widespread generalization to untreated singletons, including affricates. Moreover, there was differential generalization to untreated 2-element clusters, with individual differences being traced to the composition of children's singleton inventories. Theoretically, the results suggest a segmental-syllabic interface that holds predictive potential for determining the effectiveness and effects of clinical treatment as based on the notion of linguistic complexity.

Syllable onsets: clusters and adjuncts in acquisition

The Sonority Sequencing Principle is a presumed universal that governs the permissible sequences of consonants within syllables. In two single-subject experiments, we evaluated this principle as applied to the acquisition of onset clusters and adjuncts by children exhibiting functional phonological delays (age in years;months: 3;2 to 7;8). Experiment 1 tested the hypothesis that children abide by the Sonority Sequencing Principle in development, such that the occurrence and use of marked true clusters implies unmarked clusters, but not vice versa. This claim was validated, in part, by the gradient generalization learning patterns of children who were taught marked clusters. Others who were taught unmarked clusters exhibited limited learning characteristic of within-class generalization, with apparent gaps in sonority sequencing. Experiment 2 examined the role of adjunct sequences /sp, st, sk/, whose markedness status is questionable given their violation of the Sonority Sequencing Principle. Results indicated that children learned adjuncts consistent with patterns of within-class generalization, thereby supporting the view that these sequences are unmarked in structure. Experimental findings are integrated in discussion of the representation of onset clusters and their course of emergence in phonological acquisition relative to the Sonority Sequencing Principle.