Mihi est from Brythonic to Breton II: The nominative object

Middle Breton (MB) presents a singular anomaly of pronominal argument coding. Objects are accusative proclitics save in two constructions, where coding is split by person: 3rd unique enclitics ~ 1st/2nd accusative proclitics. The constructions are HAVE, from Insular Celtic mihi est, where the new coding replaces inflectional nominatives (cf. Latin mihi est ~ sunt); and imperatives, where it replaces accusative enclitics in V1 (cf. French aide-moi ~ ne m’aide pas). Part I followed HAVE as dative clitic subject + BE from (1) Brythonic through (2) Breton-Cornish and the HAVE-perfect of Breton. Part II traces the history of object coding: (3) Independent > enclitic coding originates in unavailability of accusative object mesoclitics in V1 imperatives by Vendryes’ Restriction in Brythonic, and nonagreement with nominative objects of mihi est in Breton-Cornish. (4) Restriction of enclitics to 3^rd person originates with mihi est in typically nonhuman nominative object possessa in Brythonic or Breton-Cornish; it spreads to imperatives through shared enclitic coding in MB, and is circumvented by the MB innovation of accusative proclitics for mesoclitics that allows 1^st/2^nd person even in V1, as well as the participle in the new HAVE-perfect later in MB. (5) “Innovative” varieties of Breton transition to regular accusative objects with or without losing dative subjects of mihi est. The developments are constrained to familiar patterns of nominative/anomalous subject + accusative/nominative object case combinations, giving rise to the imperative + HAVE construction grouping of Finnish within the history of Breton.