Expressing displacement in heritage Cantonese: Cross-linguistic influence and structural vulnerability

Aims and objectives: Heritage languages spoken by speakers in overseas communities can diverge significantly from the language spoken in the home country. Recent investigations have suggested that some grammatical structures or features are more vulnerable than others. This paper investigates the role of cross-linguistic influence, incomplete acquisition and attrition in heritage Cantonese in contact with English, focusing on the grammar of the pretransitive zoeng-construction in displacement contexts. 
Methodology: An elicited oral production task modelled on the fruit cart experiment was used to elicit displacement instructions in Cantonese. Fourteen heritage speakers and thirteen émigré speakers participated. All had acquired Cantonese as their first language but experienced a shift of language dominance to English due to immigration and education. Seventeen native speakers of Cantonese in Hong Kong served as the baseline. 
Data and analysis: The utterances were manually transcribed and coded. Production and error rates were calculated. Statistical results revealed quantitative differences among the three groups of Cantonese speakers. The baseline speakers preferred the zoeng-construction in displacement contexts, whereas the heritage and émigré speakers made greater use of canonical and topicalization structures. Nevertheless, the zoeng-sentences produced by the heritage and émigré speakers were all grammatical and felicitous. 
Findings: The basic structure of the zoeng-construction is kept intact in less than half of the heritage and émigré speakers’ Cantonese grammar. The zoeng-construction is thus vulnerable to intergenerational language change induced by language contact and individual differences, which is partially attributable to cross-linguistic influence from English. 
Originality: This is the first experimental study to investigate the grammar of heritage Cantonese. 
Significance: The study provides new empirical evidence of structural vulnerability and variability of heritage grammar and sheds light on the role of incomplete acquisition, cross-linguistic influence and attrition in such vulnerability.