Depends on what you want to do.
These are for TTS (text-to-speech) via_voice_tts_rtk_5.tar (TTS runtime engine) via_voice_tts_sdk_5.tar (TTS software development kit)
These are for dictation (speech recognition) via_voice_dict_rtk_3.tar (dictation runtime engine) via_voice_asr_sdk_3.tar (speech recognition software devkit)
I think that is all you need. If all you want is speech synthesis, you just install the TTS stuff.
> http://www.ecn.purdue.edu/~laird/Linux/ViaVoice/
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