Complementizer agreement is not allomorphy: A reply to Weisser (2019)

Weisser (2019) reanalyzes the Breton rannig, Busan Korean interrogative complementizer alternations, and West-Germanic complementizer agreement as allomorphy instead of agreement, and proposes a set of diagnostics to distinguish allomorphy from agreement. While the cases for Breton and Busan Korean are convincing and the results coherent, West-Germanic complementizer agreement diverges in several respects. In this squib, I review the three case studies and show that the argument for analyzing West-Germanic complementizer agreement as allomorphy does not hold up. In addition, I discuss three new data points on complementizer agreement that cannot be analyzed with a PF account. Accepting that complementizer agreement is not allomorphy allows us to revise the diagnostics to distinguish allomorphy from agreement to a stricter set.