For some reason I haven’t worked out yet, SAPI4 gives a “resource busy” (or something) error when trying to test a word in the LH TruVoice pronunciation window in the speech control panel on ReactOS, but it works fine on Windows XP. Other SAPI4 programs don’t output any TTS. Clearly SAPI5 works if you do some registry stuff and copy things from Windows XP, there’s a video showing that but I haven’t gotten that working 100% either:
ReactOS
WindowsXP
TTS
SAPI4