The current study reports on the CLI of object omissions by a group of Cantonese and English bilinguals. Data show that bilingual children resemble Cantonese monolinguals in the rate of object omission, but use the non-standard KEOI structure of Cantonese, which challenges the conditions for the formulation of CLI. This may be due to the shared sentence structure of both languages. The current study not only confirms Yip and Matthews(2007)argument that CLI occurs from Cantonese to English but also from English to Cantonese. Finally, structural vulnerability depends on the interaction of various factors, including CLI, input ambiguity, language contact, and other linguistic factors at the interface.