Re-programming button found at thrift store
Forget it, these are mask-programmed or OTP chips that cannot be changed. Even worse they're COB construction from one of many mainland China chip companies that probably don't even have English datasheets. 

Cut out the board out and replace it with an inexpensive Chinese module that uses MP3 or other easily created sound file format. Either with an SD card or USB port to program. You can re-use the speaker, switch and enclosure.