This chapter extends the approach of Chapter 6 to the operation of feature checking. Some forms of agreement seem to be sensitive to whether or not the controller is right-adjacent to the target, a case in point being complementizer agreement in some Germanic dialects. It is argued that next to syntactic feature checking, there can also be postsyntactic feature checking at PF. In order for agreement to obtain, the agreeing elements must be in a local relationship. It is shown that the properties of the agreement relation between complementizer and subject are unexpected if this relation were conditioned by syntactic locality, but follow naturally if conditioned by prosodic locality. From the analysis, an account of the that-trace filter follows as well.
Keywords: complementizer agreement, feature checking, that-trace filter, Germanic