Purpose: The purpose of this study was to document, validate, and corroborate effect size (ES) for single­-subject design in treatment of children with functional phonological disorders; to evaluate potential child-­specific contributing variables relative to ES; and to establish benchmarks for interpretation of ES for the population. Method: Data…

The effect of word-level variables on expressive phonology has not been widely studied, although the properties of words likely bear on the emergence of sound structure (Stoel-Gammon, 2011). Eight preschoolers, diagnosed with phonological delay, were assigned to treatment to experimentally induce gains in expressive phonology. Erred sounds were…

Three studies of phonological knowledge and generalization were conducted with six functionally misarticulating children, aged 3-4. Results indicated that productive phonological knowledge of the sound system influenced the amount of generalization learning. The extent of generalization learning was associated with the point on the knowledge…

Reports a method of clinically inducing a phonemic split in a misarticulating child. Three stages were observed in the acquisition of this split: (1) complementary distribution (allophones of the same phoneme); (2) position-specific free variation (intermediate to the phonemic split); and (3) phonemic distribution for some morphemes (phonemic…

Two studies, one within subjects and the other across subjects, evaluated the efficacy of teaching sounds in developmental sequence to nine young children (ages three to five). Treatment of later-acquired phonemes led to systemwide changes in untreated sound classes, whereas treatment of early-acquired phonemes did not. Findings suggest…

The lexical variables of word frequency and neighborhood density were hypothesized to facilitate sound change to varying degrees. Twelve children with functional phonological delays participated in an alternating-treatments experiment to promote sound change. Results indicated word frequency was most facilitative in sound change, whereas dense…

This study evaluated whether variations in the structure of minimal versus maximal opposition treatments would result in empirical differences in phonological learning with three four-year-old boys who excluded at least six sounds from their phonetic and phonemic inventories. Results indicated that treatment of maximal oppositions led to greater…

Analyzed sound systems of six phonologically disordered children and assessed relative phonological knowledge of target sounds. After-treatment results indicated that error sounds of which the children had the most knowledge were easiest to learn. Treatment beginning with the most difficult sounds resulted in more widespread changes in the…