In order for L2 learners to communicate effectively in L2, not only must they comply with the L2 grammatical rules, they must also be able to accurately convey the focus and emphasis of a proposition in L2. The English passive voice is one such syntactic means by which speakers may place emphasis and attribute greater prominence to the semantic patient over the semantic agent. The acquisition of passives at the pragmatics-syntax interface is crucial in allowing L2 learners the ability to assign appropriate levels of prominence to different event participants in their L2 verbal communication. This book reports an empirical study in which Mandarin speakers’ online production of the English L2 passive constructions was elicited using a computer-based clip called the 'FishFilm' (Tomlin, 1995). Participants’ speech data were then analysed within the Processability Theory (Pienemann et al., 2005). This study offers a fresh perspective on the acquisition and online speech production of English passives by Mandarin speakers of varous English proficiency levels. This book should be of particular interest to SLA researchers, ESL / ELF teachers and other language professionals.