The forum has 2k+ of members could there not be a sticky up requesting those willing sign up to record the individual lines of speech? Obviously, someone with the know how would write an idiots guide and explain what progs and what lines are required. There must be dozens of different countries represented on this forum.
I wouldn't mind synthesized voices. I figure there are a lot of different languages in the systems, so the voice giving you clearance is not the being at the station; it's your computer relaying the clearance to you.
Here's an idea: Add queue position sounds.
"(boopboop) Hold for clearance." "Queue position:" "three."
"Queue position:" "two."
"Queue position:" "one."
"(bing!) Docking authorized."