Risk factors associated with small expressive vocabularies in Portuguese speaking toddlers

This study investigates the individual and contextual factors associated with small expressive vocabularies in Portuguese-speaking toddlers. Data were drawn from the validation study of the European Portuguese MacArthur-Bates Communicative Development Inventory: Words and Sentences, which included 1,042 children between the ages of 24 and 30 months. Boys were nearly three times more likely to have a small expressive vocabulary than girls. Later entry into childcare and lower maternal education were also significant predictors. In contrast, birth order had no significant effect. The probability of having a small expressive vocabulary increased with the number of co-occurring risk factors, thus, underscoring the multifactorial and ecological nature of early language development.
This work was financially supported by Portuguese national funds through the FCT (Foundation for Science and Technology) within the frameworks of the Research Centre on Child Studies of the University of Minho, reference UID/00317/2025, the Center of Linguistics of the University of Lisbon, reference UID/214/2025 (https://doi.org/10.54499/UID/00214/2025) and the Psychology Research Center of the University of Minho, reference UID/01662/2025 (https://doi. org/10.54499/UID/01662/2025).