How to sound like the aliens from Mass Effect?

I tried browsing, but only came up with dead threads and a series of videos where the person who's supposedly "teaching" the viewers barely explains how to properly maintain the program in question. These videos are also slightly outdated and I've spent the last few hours trying to create a drell and quarian voice unsuccessfully. Could anyone help me out with this? I really need to get this working somehow.

Here are the tutorials:





I really need to figure out how to do this; if I fail to properly handle the sound effects for the alien species for my project, it might as well not even happen'.