In this study, 48 children with moderate or severe delays in phonological ability received treatment for four phonemes, selected in accordance with either traditional or nontraditional target-selection criteria. Children who received treatment for phonemes that are early developing and associated with greater productive phonological knowledge showed greater progress toward acquisition of the target sounds than did children who received treatment for late-developing phonemes that were associated with little or no productive phonological knowledge. Between-group differences in generalization learning were not observed. Child enjoyment of therapy did not differ between groups, but parental satisfaction with treatment progress was greater for children in the traditional group than for children in the nontraditional group.