Charest, M., & Skoczylas, M. J. (2019). Lexical Diversity Versus Lexical Error in the Language Transcripts of Children With Developmental Language Disorder: Different Conclusions About Lexical Ability. American journal of speech-language pathology, 28(3), 1275-1282.
It is well documented that the profiles of children with development language disorder (DLD) prominently feature grammatical challenges. However, evidence shows that children with DLD also struggle with word learning and use. Studies have shown that compared to children with typical language development (TLD), children with DLD frequently forget newly learned words, make more confrontation naming errors, have less robust understanding of word meanings, and need more exposures to new words in order to learn them. These results suggest that children with DLD have limited lexical knowledge when compared to children with typical language development (TLD).
Previous studies have used lexical diversity as a measure of lexical ability in children with DLD and TLD, and have shown mixed results. The authors of the current work posit that these mixed findings do not necessarily indicate that lexical ability is unreliable in distinguishing children with DLD from those with TLD. Alternatively, it may be the case that clinical measures that more accurately capture the lexical-semantic challenges noted in children with DLD are needed. The authors hypothesize that rate and type of lexical errors may be more indicative of differences in lexical ability between children with DLD and those with TLD.
In this study, 7 children with DLD and 7 children with TLD ranging from 5-7 years of age completed the Edmonton Narrative Norms Instrument (ENNI). The resulting transcripts were coded and analyzed both in terms of lexical diversity and lexical errors. Similar to previous work, various measures of lexical diversity were not found to discriminate between DLD and TLD in the current study. Lexical errors were identified by three separate coders. In total, 198 lexical-semantic errors were identified, with a significantly higher number of errors observed in the DLD group. The authors noted, however, that coding lexical errors was a highly subjective process. Only 38% of all errors in the DLD group were initially flagged by all three coders. Therefore, although focusing on lexical errors has potential for characterizing the lexical-semantic abilities of children with DLD, a detailed framework for describing these errors is needed for it to prove clinically useful.