A large-scale analysis of lexical diversity in children who stutter

Abstract

This study compared lexical abilities in 99 pairs of children who stutter (CWS), ages 25 – 100 months and age-, gender-, and SES-matched children who do not stutter (CWNS) in spontaneous conversation and on standardized vocabulary tests. Correlations among lexical diversity measures and dissociations between receptive and expressive standard scores were also calculated. CWS demonstrated similar lexical diversity compared to CWNS in measures computed for spontaneous speech, but a highly significant difference was found between CWS and CWNS on expressive and receptive standardized vocabulary scores. Despite prior reports, CWS were no more likely to exhibit dissociations on expressive and receptive vocabulary than CWNS. There were significant correlations among three measures of lexical diversity: number of different words (NDW), vocabulary diversity (VocD), and moving-average type-token ratio (MATTR). The effect that sample size and algorithms have on validity of measuring lexical diversity is discussed. Future directions in stuttering research are suggested.