https://secure.wikimedia.org/wikipedia/en/wiki/Comparison_of_speech_synthesizers has a bunch of open-source ones, but since https://secure.wikimedia.org/wikipedia/en/wiki/Speech_Application_Programming_Interface#SAPI_5_API_family should be available on modern Windows versions, probably better to target that.
https:/ /secure. wikimedia. org/wikipedia/ en/wiki/ Comparison_ of_speech_ synthesizers has a bunch of open-source ones, but since https:/ /secure. wikimedia. org/wikipedia/ en/wiki/ Speech_ Application_ Programming_ Interface# SAPI_5_ API_family should be available on modern Windows versions, probably better to target that.