I could be wrong, but the female voice while they sound fine...
There is only 1 female voice that would fit an Orc, or a Brutish (grunt grunt) kinda of character. The 3 others, or seem similar in tone.
In old BG2, I remember...(and even in NWN2), you had some sort of difference...
Like Slutry, and Idealist voice....and such.
With the female voices, I tend to use voice 2 for my working class heroes from Baldur's Gate such as urchins and others who have perhaps come from the Lower City, voice 4 is to my ears posher and a bit naive-sounding (a sort of Idealist voice, perhaps!), so I tend to use it for some of my good, Upper City type characters. Voice 6 is the one I think best fits my rougher, tougher female characters such as half-orcs, barbarians and some fighters, and voice 8 is somewhere inbetween voices 2 and 4 when it comes to poshness, but also seems to fit evil and neutral characters better than voice 2.
That's just my subjective impression, of course!