Preschoolers with speech sound disorders (SSDs) have clinically significant impairments in the production of speech sounds of the ambient language. Although many of these speech sound errors resolve after several years(with or sometimes without intervention), age-appropriate speech sound production is not always achieved. For example, in a recent large-scale study, Roulstone, Miller,Wren, and Peters (2009) reported that 18% of 8-year-olds had unresolved speech sound errors, and in another study,Sax (1972) reported that /r, s, z/ were not yet mastered by at least 7% of the fifth graders they studied.
Although many of these speech sound errors resolve after several years(with or sometimes without intervention), age-appropriate sound production is not always achieved. For example, in a recent large-scale study, Roulstone, Miller,Wren, and Peters (2009) reported that