A longitudinal study of math skills in heritage bilingual children: profiles of strengths and weaknesses.

Many children are exposed to a heritage language in the home context, and they learn mathematics in the school context in the societal language (Italian in the present study). More evidence is needed on how Heritage Bilinguals (HBs) perform in different subtypes of numeracy and mathematics skills in a longitudinal perspective. This longitudinal study aimed to analyze the mathematical skills of heritage bilingual children. 220 HBs (50.5% female, from different linguistic/ethnic groups, including Indo-Iranian, Arabic, Chinese, Romanian, Albanian and Slavic languages) and 440 monolinguals (46.8% female, mostly Italian) were followed from second to third grade (aged between 7 and 9 years). The following tasks were administered: dictation, symbolic comparison, number line, mental calculation, multiplication tables, approximate calculation, problem-solving and written calculations. The results showed an advantage for HBs in approximate calculation, but they underperformed in problem-solving, multiplication tables, and mental calculations. A profile analysis highlighted the percentages of children at risk for math impairment. The study provides a longitudinal profile of strengths and weaknesses in the mathematics profile of children with HBs, with developmental trajectories that vary according to verbal load. The discussion focuses on the role of verbal load in math tasks in the assessment of HBs, and implications for clinical and educational contexts.