Chinese is a topic-prominent language, making it typologically distinctive compared to many other languages (Li & Thompson, 1976). In this work, processing of topicalized sentences is investigated based on the performance theory of word order (Hawkins, 1994, 2004) and theories of syntactic complexity (Gibson, 1998, 2000). Factors facilitating language processing, particularly contextual background, have been illustrated in detail in existing research (Bransford & Johnson, 1972; Choi & Chan, 2006; Kaiser & Trueswell, 2004; Moore & Carling, 1982). In particular, Kaiser and Trueswell (2004) have demonstrated the importance of discourse context to the processing of noncanonical constructions. Previous studies (Ching, 2008; Hawkins, 2004; Matthews & Yeung, 2001; Yamashita & Chang, 2001) show that the length of the head-final NP in a sentence also affects the efficiency of processing the stentence.

This study investigates the processing of canonical (SVO) sentences vs. OSV sentences with a topicalized object in Cantonese. Two experiments are designed to test whether a contextual effect favoring topicalization can be induced experimentally, whether there is an intrinsic processing cost associated with topicalization, and whether topicalization is favored with longer objects. This study employs a self-paced, sentence by sentence reading paradigm to measure the reading time per sentence by native Cantonese speakers in both experiments. The resutls show that canonical (SVO) sentences have a clear advantage over topicalized (OSV) sentences even under conditions favoring topicalization, namely the presence of relevant context and heavy object NP. The findings suggest an intrinsic processing cost associated with topicalization, which may be formulated in terms of reconstruction.