Jügel, Thomas. 2013. The verbal particle BE in Middle Persian. Münchener Studien zur Sprachwissenschaft 67(1). 29–56.
Read the article here. Abstract:
The verbal particle BE in Middle Persian can be linked to three Old Iranian inputs: an adverb and an emphatic particle, both inherited from Proto-Indo-European, and an Old Iranian adverbial compound. After a short overview of previous studies, the use of various forms of BE in Middle Persian will be exemplified and the semantic and functional development will be discussed.