What I did was auto generate not just names, but the whole voice files with computer voice using the voice handler, and then overwriting them.
You do this by Options -> Auto-Generate Text to Speech files -> All lines
and then selecting the (mod/assets/lang/eng/voices/level_name) folder
I would advice comparing with frictional's original files to see what is wrong.
as well you can reference how it was done in my FUGA mod:
(note some users have experienced crashes with the moddb download, but files should still be accessable for reference. )
http://www.moddb.com/mods/martin-and-koopars07/#5711165
Also make sure to test first that it works with the computer generated voice at all, otherwise there is something wrong with how you setup the .lang/script