Lexical diffusion, as characterized by interword variation in production, was examined in phonological acquisition. The lexical variables of word frequency and neighbourhood density were hypothesized to facilitate sound change to varying degrees. Twelve children with functional phonological delays, aged 3;0 to 7;4, participated in an alternating treatments experiment to promote sound change. Independent variables were crossed to yield all logically possible combinations of high/low frequency and high/low density in treatment; the dependent measure was generalization accuracy in production. Results indicated word frequency was most facilitative in sound change, whereas, dense neighbourhood structure was least facilitative. The salience of frequency and avoidance of high density are discussed relative to the type of phonological change being induced in children's grammars, either phonetic or phonemic, and to the nature of children's representations. Results are further interpreted with reference to interactive models of language processing and optimality theoretic accounts of linguistic structure.

This study grew from a need identified by professionals working in the same community to explore interagency support for augmentative and alternative communication device implementation with students, families, and professionals involving the local school system and university. A case study was used to document intervention with a second-grade student who had developmental and severe expressive language delays. Based on the collaboration that was initiated between university and school corporation during the device acquisition process, it was determined that an interagency support system for this student would provide the best long-term solution for training, implementation, and maintenance related to her device. The participant’s intervention progress before and after intervention was described using tests and video interactions. Interviews with the principal collaborators (two speech and language pathologists) and the parent were conducted post intervention. Findings revealed positive changes in performance on the receptive and expressive vocabulary testing and scores on communication functions used based on video analyses before and after intervention. Spontaneous device use at home and school was, however, limited. As the study represented one case, no further statistical analysis was conducted. Finally, some reflections on the process were provided by the two main interagency collaborators as well as the mother of the participant, and implications for future intervention were discussed.

No abstract

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.

There was no significant difference in the overall cost for the 3-month episode of care for patients treated with either enoxaparin or unfractionated heparin. Additional acquisition costs for anticoagulant medication among patients treated with enoxaparin were offset by savings associated with lower incidence of hospital readmission and shorter duration of venous thromboembolism-related readmissions.