So, this is what I’m working with for the Neimoidian voices. In this particular scene, they are speaking Neimoidian, obviously. I also have the Viceroy speaking English to the pilot at the beginning of the film, but he speaks Neimoidian to the Queen.
https://www.youtube.com/watch?v=2uTSdXMvPco&feature=youtu.be
They sound pretty good to me, although the protocol droid sounds to me like a rearranged. IMO the droid should speak english but if you want to record a new voice for it, it doesn’t have to be a girl.