| Purpose. Fricatives are a class of sounds that is considered difficult to produce, and are generally developed later than stops, nasals and glides in speech sound development. Current understanding of fricative development suggests that children who develop fricatives at an early age may have better expressive language skills than children who do not develop fricatives early. The purpose of this study was to investigate the changes in fricative production, overall consonant production, and vocabulary growth in a group of toddlers who participated in a short-term, intensive auditory-perceptual intervention program.;Methods. The study sample consisted of eight typically developing 18-month-old toddlers with half (n=4) in the treatment group and half (n=4) on the control group. Each toddler in both groups was visited 3 days a week for a period of 3 weeks. During each visit, a 15-minute session with a book-reading activity with a specially designed book and a play activity using selected toys and a play-script was conducted. The treatment group toddlers participated in an auditory-perceptual intervention with the book and the script designed to provide stimulation for the sounds /s/ and /z/. The control group toddlers participated in similar activities, however with materials designed to avoid stimulation of /s/ and /z/ sounds. Children's performance was assessed with speech samples and the vocabulary scores obtained at pre-treatment, post-treatment, and when the child reached 20 months of age (follow-up). A speech sample was also collected from each child before every treatment session. The assessment data were statistically analyzed to look at the differences in speech sound production and vocabulary over time for both groups of toddlers.;Results. The number of fricative /s/ and /z/ productions, number of fricatives, number of fricative types, percentage of fricative types and vocabulary raw scores significantly changed over time for toddlers of both groups combined from pre-treatment to post-treatment and/or follow-up sessions. No significant group effects or interactions between group and time were found for any of the outcome measures. Individual data revealed that 7/8 participants produced fricatives and all 8 of the toddlers increased their vocabulary raw scores from pre-treatment to post-treatment and/or follow-up session.;Conclusions. All toddlers enrolled in the intervention completed the intervention as planned. Fricative production and overall vocabulary changed over the study period of 2 months (between 18--20 months) for toddlers of both groups, regardless of stimulated for fricatives or not. There is no evidence from this study that targeting fricatives using an auditory-perceptual method was helpful in phonological and vocabulary development. The lack of differences between the groups suggests that general language stimulation rather than specific fricative stimulation may result in the development of fricatives. Hence, early intervention programs with more general rather than specific stimulation may be appropriate and beneficial for toddlers identified with or at-risk for speech and language delay. The evidence that toddlers as young as 18 months of age are able to participate in a structured intervention program suggests that such programs might be viable for children who are at risk for speech and language delay. |
