As literature written in Latin has almost no female authors, we are dependent on male writers for some understanding of the way women would have spoken. Plautus (3rd to 2nd century BCE) and Terence (2nd century BCE) consistently write particular linguistic features into the lines spoken by their female endearments, soft speech, and incoherent focus on numerous small problems. Dorota M. Dutsch describes the construction of this feminine idiom and asks whether it should be considered as evidence of how Roman women actually spoke.
I was really hoping for more work along the lines of Adams' 1984 Autochthon article or Gilleland's dissertation, but Dutsch provides very little in the way of additional analysis of the actual linguistic details of female characters' speech patterns in Roman comedy, instead focusing on character portrayal and critical theory. Not exactly what I was wanting out of it.