We thank Mr Kwan Jin Yao for his interest in our study ("Assess Chinese-language proficiency more rigorously"; July 15).

The Singapore Centre for Chinese Language deeply appreciates his suggestions.

This two-year research had its design and assessment tools rigorously constructed and reviewed by educational professionals.

The major research question of our study was on the relation between children's home language environment and their language ability.

Such a relation was, therefore, the focus of the report on July 15.

Generally, our findings corroborate the findings from previous studies, which showed that a combination of socio-economic factors has impact on children's language abilities.

Many of these factors, including family socio-economic status, are intricately inter-related, and would require further discussion and research.

We agree with Mr Kwan that longitudinal research can be carried out to provide more insights on Singapore's language environment and its effect on language learning and bilingual development, given that home language, school transitions and social mediation affect children's language development over time in varying degrees.

The Singapore Centre for Chinese Language will look into the possibilities of longitudinal research to understand how our pre-school children acquire and develop their languages in Singapore's unique language environment.

Tan Chee Lay (Dr)

Principal Investigator

Pre-school Research Team

Singapore Centre for Chinese Language