My understanding of this (and I don’t know Greek), is that the case ending makes it impossible to tell if this name is female or male.  This has nothing to do with an 'accent.'  However, Ehrman not only alerts me to this issue of Junia/Junias, but explains that “whereas Junia was a common name for a woman, there is no evidence in the ancient world for ‘Junias’ as a man’s name.”  The King James Bible (~1611 CE) has Junia as a woman.  So does the Catholic NAB on the Vatican website.  Here is the Catholic NAB:  Romans 16:7:  “Greet Andronicus and Junia, my relatives and my fellow prisoners; they are prominent among the apostles and they were in Christ before me.”  The footnote lets you know she is a woman.