Although children with specific language impairment often show significant limitations in their use of grammatical morphemes, little is known about their use of morphemes that belong to a single set or paradigm. This question was pursued in the present study by examining specifically language-impaired (SLI) children's use of the Italian definite article system. Fifteen Italian-speaking SLI children were found to produce all articles with lower percentages than a group of 15 control children matched for mean utterance length. However, both groups had greater difficulty with plural articles than singular articles, and more difficulty using articles with restricted phonetic contexts than articles with a freer range of permissible contexts. In addition, the SLI children's difficulty with one of the articles seemed attributable to phonotactic constraints. The findings are interpreted within a framework that assumes that SLI children split and fill out morphological paradigms in the same manner as younger normally developing children, but operate with a more limited capacity that is burdened when grammatical morphemes have difficult surface characteristics.