Acquisition of Chinese as a second language (CSL or L2 Chinese) is a newly developed discipline that aims to study the process by which non-Chinese speakers learn Chinese as a second or foreign language. The language produced by CSL learners is interlanguage in CSL. According to Selinker’s interlanguage theory (Selinker 1972, Selinker et al. 1975), interlanguage is a separate linguistic …