The goal of the current study was to construct a reference database against which misarticulations of /s/ can be compared. Acoustic data for 26 typically speaking 9- to 15-year-olds were examined to resolve measurement issues in acoustic analyses, including alternative sampling points within the /s/ frication; the informativeness of linear versus Bark transformations of each of the 4 spectral moments of /s/ (Forrest, Weismer, Milenkovic, & Dougall, 1988); and measurement effects associated with linguistic context, age, and sex. Analysis of the reference data set indicates that acoustic characterization of /s/ is appropriately and optimally (a) obtained from the midpoint of /s/, (b) represented in linear scale, (c) reflected in summary statistics for the 1 st and 3rd spectral moments, (d) referenced to individual linguistic-phonetic contexts, (e) collapsed across the age range studied, and (f) described individually by sex.

This study examined long-term changes in articulation rate (the pace at which speech segments are produced) and phonetic phrase length in the conversational speech of two groups of children with speech delay (SD) of unknown origin. Initial testing for both groups occurred at preschool age, with follow-up testing conducted for the Early Follow-Up Group (n = 17) at age 9 years and for the Late Follow-Up Group (n = 36) at age 12-16 years. At follow-up testing both groups produced significantly faster articulation rates (measured in both syllables per second and phones per second) and significantly longer phonetic phrases (measured in both syllables and phones) than at initial testing. Articulation rates at both test times were also judged to be similar to published values from typically developing children of similar ages when measured in syllables per second. However, findings for rate in phones per second suggested that at least at initial testing the children were articulating speech at a slower rate than their typically developing peers. This latter finding, however, may have been an artifact of the high frequency of errors--such as cluster reduction and final consonant deletion--observed in the initial samples. It would appear, therefore, that children with SD of unknown origin may start out with slower than normal articulation rates but eventually catch up to their typically developing peers.

Conversational speech is the most socially-valid context for evaluating speech intelligibility, but it is not routinely examined. This may be because it is difficult to reliably count the number of words in the unintelligible portions of the sample. In this study four different approaches to dealing with this problem are examined. Each is based on the assumption that it is possible to perceive syllables in unintelligible strings even when the target words are unknown; these unintelligible syllables can then be used to estimate the number of unintelligible words in these samples using at least four different approaches. Preliminary data are presented for each of the four approaches based on conversational speech from two convenience samples including 320 children with normal (or normalized) speech and 202 children with speech delay. Differences among the four approaches are discussed.

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The goals of this study were to estimate the risk for lowered speech-language outcomes associated with early recurrent otitis media with effusion (OME) with and without hearing loss and to develop a preliminary descriptive-explanatory model for the findings. Three statistical approaches were used to assess associations among OME, hearing loss, and speech-language outcomes. Participants were a subsample of 70 children followed prospectively in the Dallas Cooperative Project on Early Hearing and Language Development (Friel-Patti & Finitzo, 1990). Findings indicated that hearing levels at 12-18 months were significantly associated with speech delay and low language outcomes at 3 years of age. The risk for subclinical or clinical speech delay at 3 years of age was 2% for children with less than 20 dB average hearing levels at 12-18 months and 33% for children with greater than 20 dB average hearing levels at 12-18 months. A structural equation model (Jöreskog & Sörbom, 1993) indicated that the significant and substantial effects of hearing levels at 12-18 months on speech status at 3 years were significantly mediated by language status at 3 years. Discussion includes implications of these findings for alternative speech perception models linking early OME and hearing loss to later speech-language disorder.