Egads! Check out this video which predicts the future of computing... in particular, the TTS is... well, what better way to put it... just like a real person via a video! (Oh my, I do believe it IS a real person). At any rate, it's quite interesting from a historical perspective. Apple - nor any other competitor - hasn't quite made this scenario available.  At any rate, while the SR might be there - given a more limited context - the TTS still has a longer way to go to emulate the 'real speech' in this video.