Exploring diachronic universals of agreement: Alignment patterns and zero marking across person categories

Two principles shaping agreement paradigms have been implicitly assumedto constitute diachronic universals: (i)ergativity is assumed to bemore likely to develop or be maintained in third than in non-third person; (ii) zeros are assumed to develop and be preserved more commonly in third than in non-third person. Estimating probabilities of diachronic change in a worldwide database and controling for areal diffusion effects, we find no evidence for (i). Principle (ii) receives no support either when examining how paradigms develop as systems, but we observe a weak cross-paradigm effect which is likely to be caused by frequency patterns during grammaticalization.