I don't really see the need for two files....
From what I can see, what you want is some kind of alarm-clock that instead of playing a laud sound will "say" the time..
It seems simple to do, but You'll have to have the Wave, mp3 or whatever sound bits you need created by you...
Then in a timer keep checking for the system time and compare it to the setted time, if this is an alarm-clock, or check for the hour value, and if true play the sound file...
P.S.: If this is to be Open-Source, I am trying to create an on-line partnership to develop Open-Source projects....