Thread:User talk:CodeCat/Balto-Slavic glottal stop/reply (10)

Matasović says this about it:

The change *o > *a must be placed after Winter's law, because original *o lengthened as Lith. uo, and original *a (from *h₂e) is lenghtened as Lith. o, [...] Kortlandt (1985) thinks that the change of *o to *a and of *ō to *ā are parallel processes occurring in Proto-Slavic, which mean that the identical change of *o to *a in Baltic is an independent development. However, it is more economical to assume that the merger of short *a and *o was a common Balto-Slavic innovation.