Supplementary Material for: Validation of an Italian grammatical comprehension test for children: individual and family influences on receptive language

Introduction. The study aimed to validate a grammatical comprehension test for Italian-speaking children (TCGB-2; Test di Comprensione Grammaticale per Bambini – seconda versione) and examine the influence of individual and familial factors on grammatical comprehension in Italian-speaking children. A relevant feature of the TCGB-2 is its inclusion of specific grammatical structures scores, which enhances its clinical relevance.
Methods. A multicentre observational study on 452 Italian-speaking children aged 3;6–8;11 (years; months) was conducted. Psychometric evaluations included item analysis, internal consistency, test-retest reliability, and construct validity, encompassing Confirmatory Factor Analysis, convergent validity, and discriminant validity. Differences based on age, gender, parental socioeconomic status (SES), area of residence, and language exposure were also examined, alongside non-verbal reasoning and phonological memory.
Results. The TCGB-2 demonstrated strong psychometric properties, including acceptable reliability, validity, and factorial structure. Statistically significant differences in comprehension scores were observed based on age, gender, and SES, with higher scores for older children, females, and children whose parents have higher educational and professional backgrounds. Non-verbal reasoning and phonological memory showed weak correlations with grammatical comprehension. The inclusion of varied grammatical structures provided a detailed profile of the developmental learning trajectory for each grammatical type.
Conclusion. The TCGB-2 is a valid and reliable tool for assessing grammatical comprehension in Italian children, with its different grammatical structures offering added clinical insight. Findings underscore that age, gender, and SES contribute to language comprehension. These factors should be considered in clinical practice to better support children with language comprehension needs.