un_ax

I was curious and it uses gTTS.

It calls what's probably the "speak" button on translate.google.com

This project is leveraging the undocumented Google Translate speech functionality

You could use WPAD on your network to point all clients to an i2p proxy. I'm not sure sure if it's secure or private to be able to access both at once though.

function FindProxyForURL(url, host)
{
  if (shExpMatch(host, "*.i2p"))
  {
    return "SOCKS5 [proxy ip]:4447";
  }
  return "DIRECT";
}