Lexical diversity in bilingual speakers of Croatian and Italian
Gordana Hržica, Maja Roch · Trends in language acquisition research · 2021
Abstract The aim of this study was to determine whether measures of lexical diversity (LD) can be used to assess general lexical knowledge. This study focused on 30 sequential Croatian/Italian bilinguals aged between 5 and 7 years, who were compared with 30 Croatian and 30 Italian monolinguals matched in age. LD was assessed from narrative language samples using standard measures and compared with Peabody Picture Vocabulary Test (PPVT) results. Two LD measures, the type-token ratio (TTR) and Maas Index based on TTR transformation, did not differentiate between bilinguals and monolinguals, whereas several other did: total number of words (NTW), number of different words (NDW), measure D, moving average type-token ratio (MATTR) and hypergeometric diversity of D (HD-D). NTW, NDW, D, MATTR and HD-D were predictive of PPVT results for monolinguals, whereas NDW, TNW and D (with replacements, Dr) were predictive of PPVT results for bilinguals. Our results suggest that LD measures can be reliable measures of bilinguals’ vocabulary knowledge and can adequately reflect PPVT results in languages other than English.