In this study, a system was developed to offer adaptive remedial instruction materials to learners of Chinese as a foreign language (CFL). The Chinese Listening and Speaking Diagnosis and Remedial Instruction (CLSDRI) system integrated computerized diagnostic tests and remedial instruction materials to diagnose errors made in listening comprehension and speaking. To test the CLSDRI system, 65 CFL students were recruited from the Mandarin Training Center at National Taiwan Normal University to participate in an experiment. The results indicated that the CLSDRI system made a greater positive impact on the experimental group (EG) participants' listening comprehension and oral language proficiency compared with the control group's (CG) use of computerized diagnostic tests combined with paper-based remedial instruction materials. Moreover, the experiment revealed two interesting findings related to the effectiveness of the CLSDRI system: (1) immediate and adaptive remedial instruction materials improved the EG participants' proficiency in listening comprehension and speaking and (2) there were fewer differences in listening comprehension and speaking abilities between the Sinosphere participants who resided in a Chinese population and were influenced by Chinese culture and the non-Sinosphere participants. These findings support the effectiveness of computer-assisted language learning.