In a study testing bilingualism development in children, a child shows results indicating that professional language ability is much better in L2 than in L1.

It can be inferred from this result that the child acquired L2 in which manner?

1) Both parents spoke L1 and L2
2) One parent spoke L1 and the other spoke L2
3) The child learned L1 at home and L2 at school
4) The child learned L2 at home and L1 at school

A child with better professional language skills in L2 than L1 likely learned L2 at home, which is supported by findings that early and proficient second language acquisition enhances cognitive outcomes. So, the correct option is 4) The child learned L2 at home and L1 at school.

Explanation:

When a bilingual child demonstrates a professional level of language ability in their second language (L2) that surpasses their first language (L1), this can indicate that the child likely had a more immersive and substantial exposure to the L2. Considering the literature on bilingualism, it suggests that children acquire language efficiently through consistent and dense exposure, such as being immersed in the environment where the language is natively spoken. Therefore, it can be inferred that the child most likely learned L2 at home and L1 at school (Option 4). This rationale aligns with research findings which propose that cognitive abilities are enhanced when a second language is learned earlier and with higher proficiency (Mechelli et al., 2004).