Cover -- 1. Editorial -- 2. Editorial -- 3. Editorial -- Abstract -- Acknowledgements -- Abbreviations -- Contents -- 1. Introduction -- 1.1 Addressing the object of enquiry -- 1.1.1 The two (pivotal) "whys" in this book -- 1.2 Outline -- 2. Argument licensing and voice alternations -- 2.1 Theoretical background -- 2.1.1 Argument licensing, argument structure and voice alternations -- 2.1.2 Is the subject an argument of its verb? -- 2.2 Unaccusativity -- 2.2.1 Unaccusative morphology and syntax: Form vs. structure -- 2.2.2 Argument structure in passives and other unaccusatives -- 2.2.3 So who (or what) is the subject of impersonals? -- 2.3 Case and agreement in impersonals -- 2.3.1 Default agreement and morphological underspecification in impersonals -- 2.3.2 Acc licensing and Cause/Voice parameterisation -- 2.3.3. Case/DP licensing in impersonals -- 2.4 Chapter summary -- 3. Previous L2 research: An overview -- 3.1 L1A vs. L2A -- 3.2 UG or not UG? -- 3.3 Syntactic impairment in L2A? -- 3.3.1 The L2A of ImpPass -- 3.4 Underspecification and morphological deficits -- 3.4.1 Further evidence: Underspecification in L1A -- 3.5 L2 straddling the interfaces -- 3.5.1 The Interface Hypothesis: an outline -- 3.5.2 Reconciling facts and fitting them into theory: First step -- 3.6 Chapter summary -- 4. Parametric variation -- 4.1 On the EPP and expletives -- 4.2 Pro-drop -- 4.3 Impersonals, passives, and voice alternations cross-linguistically -- 4.3.1 Russian impersonals -- 4.3.2 German impersonals -- 4.3.3 L1s in the 'L2 GE' study -- 4.3.3.1 Slavic impersonals -- 4.3.3.2 Romance impersonals -- 4.3.3.3 Chinese -- 4.3.4 Interim summary -- 4.4 Parameters and clustering effects in the languages under investigation -- 4.5 The L2A of arguments and voice alternations: Research questions and hypotheses -- 4.6 Chapter summary -- 5. Two studies.

5.1 Methodology, informants, and data elicitation -- 5.1.1 The cloze test -- 5.1.2 The Grammaticality Judgement Task -- 5.1.3 Data acquisition and informants -- 5.2 'L2 GE' and 'L2 RU' tests: Description -- 5.2.1 The 'L2 GE test' -- 5.2.2 The 'L2 RU test' -- 5.3 Statistical evaluation - technical details -- 5.3.1 The Null Hypothesis -- 5.4 Results -- 5.4.1 'L2 German' findings -- 5.4.1.1 Mixed data evaluation across levels of L2 GE proficiency -- 5.4.1.2 Parameter-based evaluation -- 5.4.2 'L2 Russian' findings -- 5.4.2.1 Data evaluation across levels of acquisition -- 5.5 Chapter summary -- 6. Discussion: On the complexities of L2 syntax -- 6.1 The nature of L2 knowledge -- 6.1.1 Argument and event structure in L2A -- 6.1.2 Impersonal constructions in L2A: syntax, semantics, and discourse -- 6.1.3 On zero, bound, and free pronouns: Referentiality in L2A -- 6.1.4 The L2A of empty categories and expletives -- 6.1.5 Case and agreement in L2A -- 6.1.6 Interim summary -- 6.2 Exploring and explaining optionality in interlanguage grammars -- 6.2.1 The dynamics of linguistic knowledge: Native speakers' vs. L2ers' judgements -- 6.2.2 Phases, functional domains, L1 transfer, interfaces: Which one is responsible for the variability in L2A? -- 6.2.2.1 Phases and functional domains -- 6.2.2.2 L1 transfer and positive evidence -- 6.2.2.3 Interfaces -- 6.3 L2 morpho-syntax -- 6.3.1 Representational deficits in light of the principle of Underspecification and linguistic defaults -- 6.3.2 Overgeneralisation in L2A and learner defaults -- 6.3.3 (Anti)causatives, impersonals, and (non-) canonical patterns in L2A -- 6.4 Chapter summary -- 7. Concluding remarks -- References -- Appendix A: 'L2 GE test' -- Appendix B: 'L2 RU test' -- Appendix C: Answers.