Converting text to mp3

[Linux for blind general discussion]

On a somewhat related note, does anyone know of anything that can take
a subtitle text stream(generally plain text, usually .srt or .ssa when
not muxed in To a video file) and spit out audio of the dialog that's
timed to the timestamps in the subtitle file? Bonus points if,
assuming the subtitle script includes character tags, there's a way to
set different synthesized voices for different characters. Would be
handy for media that has English softsubs, but no English audio...
though even just a means of converting .srt or .ssa to something more
human readable would be useful.