Indogermanische Forschungen. Zeitschrift für Sprachwissenschaft. — 2018. — 123. Band. — S. 211-246.
The East Baltic conditional mood (e.g. Old Lithuanian duotumbiau ‘Iwould give’) must certainly represent a recent innovation of this branch of Indo-European, but its origin raises considerable problems. At first glance it derives from a periphrasis combining the inherited supine (e.g. duotun ‘giving’) and an auxiliary *bi- of obscure origin, probably an optative or an indicative preterite of *bhuH- ‘to be’. Semantically, this periphrastic structure is difficult to account for, especially if one recalls that the supine is limited to the expression of finality after verbs of motion, which cannot have been the case with an auxiliary ‘to be’. In addition, the absence of an auxiliary in the third person in Lithuanian (e.g. duotų ‘he/they would give’) and throughout the paradigm in Latvian (e.g. es, tu, viņš duotu ‘I, you, he would give’, etc.) requires an explanation. In this paper I try to give a full account of the prehistory of the East Baltic conditional mood, relying on Stang’s analysis but with a more precise scenario to explain some syntactic and semantic aspects which have not yet received the attention they deserve.”