This paper reports on an experimental study in which bilingual English-Cantonese university students were asked not to speak any English for one day and to write a reflective diary on the experienced communication problems. The findings indicate that a theoretical model of code-alternation that claims universal validity and explanatory adequacy, needs to take into account the bilingual's concern for referential meaning. The sociolinguistic and educational impact of these results for the Hong Kong speech community are briefly discussed.