Standard Written Chinese is expected to be scripted or recorded in Putonghua expressions, the national lingua franca in China. However, due to the influence of mother tongue, Hong Kong students often unconsciously employ Cantonese dialect expressions in their writing. This paper introduces CPWrite, an implemented Web-based CALL package to help tackle this problem. The important functions of the software are to test and improve students' ability in Cantonese dialect recognition and Putonghua translation, at both lexical and grammatical levels. The underlying strategies employed by CPWrite can be applicable to converting authentic language to standardized formats.[Copyright of Computer Assisted Language Learning is the property of Routledge. Full article may be available at the publisher's website: http://dx.doi.org/10.1076/call.16.4.367.23413]