Maternal heritage language proficiency and child bilingual heritage language learning

‘Should I talk to my child in a language that I am not good at?’ This question reveals the dilemma that many bilingual parents are facing. In the current study, 301 English-Mandarin bilinguals’ mothers in Singapore self-evaluated their Mandarin proficiency and we assessed the 4–5 years old children’s Mandarin receptive vocabulary and grammar. We also investigated children’s bilingual language exposure with a parental questionnaire and children’s phonological short-term memory with CTOPP. The results indicated that mothers’ Mandarin proficiency would affect the amount of Mandarin they speak to their children. Those mothers with a medium- or high-level Mandarin proficiency demonstrated a significantly stronger influence on children’s Mandarin vocabulary and grammar than the mothers with lower Mandarin proficiency. Specifically, mothers’ Mandarin proficiency mediated the relations between familial SES and children’s Mandarin skills after controlling children’s Mandarin exposure at home, gender, and short-term phonological memory. Our findings suggest the unique role that maternal Mandarin proficiency plays in early heritage language learning. It indicates that mothers who have a decent command of heritage language should be encouraged to use this language more often with their children, considering maternal heritage language proficiency as a promotive factor from the influence of low SES.