Topicalization is the preposing of object to the beginning of the sentence. This reordering is widely used in Cantonese. According to Hawkins (1994), topicalization could shorten the constituent recognition domain (CRD) of the sentence. He predicted that this shortening would enhance the recognition of sentence constituents and hence speed up the time for understanding. The preference for topicalization should increase with the length of the object noun phrase.

A reading time test is carried out on these predictions. Subjects are asked to read a topicalized (Object-Subject-Verb order) version and an ordinary Subject-Verb-Object version of a given sentence. The differences between these two reading times are analyzed using statistical methods. The results suggest that topicalization is preferred for sentences with object modified by relative clause, while no preference is made for sentence with short object noun phrase. These results are consistent with the prediction of Hawkins' theory.