I dont think it has anything to do with your iGO version myself.
That svox voice I gave you sounds excellent with Victoria svox.
Are different languages available in android voice input and output settings. Try en_us or en_au if available then select listen to a demo at the top to see if they work.
Try editing the actual voice.zip file and look for these lines to read:
tts_langname="en-GB"
tts_engine="android"
As previously mentioned remove any phoneme files, I was suprised what a difference this made.
If all else fails then try uninstalling your tts voice engines and try installing this one. It looks a bit complicated but works just fine.
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