[INDOLOGY] Schwa deletion in the medieval/early modern period?

[Martin Gansten]

I'd be grateful for any pointers as to what is known of the history of 
schwa deletion in Indo-Aryan languages -- particularly, whether it had 
begun (and if so, how far it had progressed) in the period between, say, 
1000 and 1500 CE. This is not my usual field of study at all, so 
references even to the most basic sources would be appreciated.

Martin Gansten