<div> First of all let me make you aware that I use DragonDictate, as I can't see very well and proofreading is quite painful so you'll have to forgive and interpret from mistakes the DragonDictate may make. It</div>
<div> I was taught about form and speech synthesis by Dennis Klatt, and by reading but before my involvement with him I knew next to nothing. One of the questions in the early days was could you achieve higher intelligibility by super articulation and do better than natural speech. What testing revealed was really two things. At normal speaking rates the answer always seem to be that the closer you matched to real speech the better the intelligibility at higher speaking rates above that which humans could normally achieve things were little different and I'm not going to go into the specifics of what we did to make things better at high speed other than to say they were based on knowledge of speech perception.</div>
<div> The second thing we learned is that listening to a synthesizer has a very fast but steep learning curve. Somewhat analogous to learning to understand a person with a strong dialect or speech impediment. One of the problems we encountered is that people often preferred the version they were used to over any succeeding version. But actual tests did not support the preference.</div>
<div> One example is the way tilt was done inside DECtalk. The original mechanism was a crude approximation of spectral tilt. Dennis before he died developed a much more accurate (meaning matching human production) tilt filter that was not able to be incorporated to a later date. As a point of interest Dennis was so dedicated that he last modified the DECtalk code 3 days before he passed away. So the spectral tilt was changed and this changed what you might consider the tone control on an old radio or record player. That is just one of many reasons why DECtalk change slightly over the years.</div>
<div> The 5.0 DECtalk Incorporated the work of Prof. Ken Stevens who was Dennis is blessed MIT and close friend. The 5.0 code unfortunately did not yield the expected results, but we did learn a lot from the attempt. This</div>
<div> there are even some changes to DECtalk that would change the way it sounds from any particular version, such as Intonation that I am unwilling to revert because I know for a fact that they caused loss of information. So my goal is very simple I am working to create a very functional intelligible DECtalk to put back out, I am unwilling to try and make it sound exactly like any given person wants to. I have been through this before and the year is very sensitive and if you directly comparing two versions side-by-side you not testing anything but whether did the same and that is an exercise in futility. T </div>
<div> </div>Any specific issues I can address. Secondly as a word of warning to listeners providing feedback. The other thing we've learned is that listeners are excellent at deciding that something is not right, but are absolutely terrible at exactly pinpointing the problem. The reason for this is quite simple people judge the output as speech which it only kinda is, by this I mean that a synthesizer can make mistakes that humans cannot possibly do and as a consequence can't possibly recognize. An example of this is that after so many years of working with it I have learned to hear a foreman that's moving too rapidly, but most people cannot hear it. This is because to make life easy we try to lead nor stuff that's not important in our language, such as the nasal lifestyles in French or the retro flex ours in American English which is Sheehan have a heckuva time hearing.