Direct assessment of vocabulary
We employed the Peabody Picture Vocabulary Test (Campbell, 1998; Dunn & Dunn, 1965) to assess children’s receptive vocabulary. This test comprises 228 colored pictures organized into four groups, resulting in 912 pictures. The testing procedure involves the examiner presenting a vocabulary word orally, and the child selects the picture that best corresponds to the word’s meaning. A correct choice receives a score of 1, while an incorrect one receives 0. The PPVT has been effectively validated in China (Xu & Liu, 2021). In the current study, we calculated the total score.