Here's a screen shot of an FM I've been building to help test/review subtitles for an AI, in reproducible order with 100% coverage. It uses the TDM-distributed .ogg files, but has custom soundshaders. Each such soundshader wraps exactly one .ogg file, and has a uniform naming that includes an index number. The collection of soundshaders is housed in a single file. The hope is that that (prior to embedment in the FM) this file can be easily generated from a directory listing of the .ogg files for a particular AI, and subsequent manipulation.
There are 3 buttons to step through the file. After each button press, you hear the vocal and see the subtitle. Also, briefly the index number within the list appears (a floating "7" near the statue's shoulder in this screenshot.) You can also - using a custom CVar in the console - jump to a particular index number.
Unsurprisingly, you can't edit the subtitle within the FM. Just note what needs changing and do it with a text editor. Also, this FM is not intended to evaluate TDM's stock soundshaders, nor AI lip syncing (so just a statue speaking here.)
If you hit the buttons fast enough, multiple sound files play at once, and multiple subtitle fields appear (up to the max of 3 the .gui offers)