V2, CP and the restructuring of IP

As outlined in section 4.5.2, beyond the implementation of the new structural layer on top of the VP, learners face the task of acquiring the target V2 constraint. Further, target-like question formation and the production of complementiser introduced subordinated clauses involve the projection of an additional structural layer, the CP. Following the asymmetry hypothesis of German sentence structure (section 4.1.4), finite verbs in embedded clauses are raised to a head- final IP so that their features be checked. On their way to the attainment of the full sentential structure, learners are thus confronted with the task of implementing an additional layer (the CP) and a head-final IP to accommodate the structural asymmetry of main and embedded clauses. What do the data of our participants reveal in this respect? Summarising, what our discussion of the individual developmental profiles showed is that by the end of the recording time not all learners have established the full sentential structure (CP) and only some of them adhere to the target V2 constraint.