I think Dr. Mozer's patent for the technology that was used in the Digitalker chip (MM54104), was licensed to NS and the vocab ROMs are copyright NS, isn't it? I had contact with mr. Mozer last year, quite an honor, still lecturing at university! And his very friendly son Todd, CEO of Sensory, but they couldn't help me with information, it was all too long ago...
The one I included in my post above, it shows an MM54104 and a Mitsubishi 256K EPROM.
I can try to repeat the URL, but it is interpreted by this message board, a picture and a short description are shown:
(I now put the URL between CODE-tags, hopefully it doesn't get interpreted).
National Semi vocab ROM's were not of the type EPROM and the maker of this device scribbled "SR1,2,5,6" on it, while the SSR1, 2, 5 and 6 were separate 64K ROM's. (separate components I mean)
Don't get me wrong, I can hardly imagine the current owner of NS (I believe that is TI) will start a legal procedure ;-)