>Hey! Are the Latin imperfect endings -bam, -bas etc. developed from adding
an earlier form of the verb 'to be' (*bhu-) to the verb stem?
Yes. Interpreting and translating loosely, "The key to understanding the
whole category is the form FUFANS in Oscan, which would correspond to an
unattested *fubant in Latin. This is by form the past of a reduplicated
perfect (making it a pluperfect in form) from the root *fu: < *bhuh
"become". Compare the Oscan perfect FUFENS < *fuBu < *bhu-bhu < PIE
*bhe-bhu. The basic meaning of this verb made it an ideal starting point
for the creation of a new verb form. The perfect "I have become" = "I am"
and so the pluperfect "I had become" = "I was". Since in proto-Italic the
reduplicated syllable fu- was interpreted as a new root, giving forms such
as futurus, the ending -ba- could be interpreted as a new suffix. From the
pattern fu- : fuba- developed the present : imperfect pattern ama- : amaba-
and so on."
Peter