title: High-quality open-source text-to-speech (TTS) engines written in C++
body: <p>I'm looking for open-source text-to-speech (TTS) engines written in C++. Ideally with high-quality voices (see quality definition below), but also lower quality alternatives are okay as long as the source is freely available.</p>
  
  <p>Does such an open source project exist?</p>
  
  <p>By "high-quality" I mean "human sounding", "non-robotic" and with end results roughly on par with these two English language examples: <a href="http://translate.google.com/translate_tts?ie=UTF-8&amp;tl=en&amp;q=This+is+an+example+to+illustrate+the+desired+level+of+quality" rel="noreferrer">Example 1</a>, <a href="http://tts-api.com/tts.mp3?q=This+is+an+example+to+illustrate+the+desired+level+of+quality" rel="noreferrer">Example 2</a></p>