That are the requirements of the SimbOS app, pitch slider, say(allophones), speak(English text) and left, right or centre selection. You can see it on the SymbOS screen I post.

There isn't volume selection, we can asume medium here

Later, if all goes right,  a good Enterprise text2speech can be done with the Amsoft code but exploiting Dave characteristics better.

There are some odd words in the list, like SUPERIOR or DAVID. I think this program is the Superior Software one, re-selled by Amsoft.

Superior Software made similar text to speech programs for other microcomputers, like for example the BBC, one of the odd words included....

https://en.m.wikipedia.org/wiki/Superior_Software

The modified code fits to it's original place also

I have finished the source code, but sjasm doesn't accept some commands of the assembler used by Prodatron.

On the other side, once compiled, the executable will have the .bin tag like the first SymbOS port we had, I don't know if it works the same as the .exe tag, common on the beta 3.0 we manage now.



Edit: the two headers look similar.

    db #dd:ld h,a

SjASMPlus can handle multiple instructions with colon.
But also possible simply convert to two lines:
     db #dd
     ld h,a

please compare aaa (compiled binary) with the original binary, there is still one error, but the reason is duplicate label, so I think something should be changed, but without original binary I do not know what.

This is the oldest appspeech I've found, from 2005.

Also I have corrected the duplicate label observing the source of other apps.

Try it, if it doesn't work we always can ask to the creator...

At last I've disassembled all the Amsoft Speech code. 

The original code weights about 8Kb, but removing the dictionary, leaving exclusively the allophones parsing, probably it can be condensed on 4Kb or less. 

The only Enterprise game that uses the Speakeasy device  is Eat-it-up, not a lot of memory demanding game, as it only weights  12,5Kb.

The way of work of the two speech systems is similar, Speakeasy receives strings of allophones(internally it works with 59 codes for the allophones plus five more codes for pauses ) through the Parallel port, and the Amsoft code also can be fed with strings of allophones.  The only problem is that the Speech code needs Z80 time to sound.

However the nomenclature of the two systems of allophones is different, but I've found easy to construct intelligible words with the Amsoft code, probably better than with Speakeasy, that doesn't admit stresses inside the words(tildes) and has the pitch fixed on Rom, unlike the Speech code.

This, thinking on a way of emulating Speakeasy, but this tiny code can be incorporated on newer games or programs easily.

Improvements on the sound can be achieved modifying the samples, but I'm not the man that can do that....