TTS edge case, asking for guidance

I’m not sure if this is the correct repo to post this to, so please move if appropriate.

Recently I have come across some edge cases where TTS software would leave out certain characters:

- An 18th-century English text that used the long s `ſ` where appropriate, which in this case I would like to preserve for purely typographic reasons. Same for German texts originally set in Fraktur if one wished to have them rendered exclusively in such a typeface.
- Some 19th-century German books where the author made idiosyncratic use of the breve and macron diacritics (not used in German), e.g., `ă` and `ā`, to indicate correct pronunciation of long and short vowels in footnotes to the text. Replacing them with the non-diacritic forms would remove essential information and render the footnote obsolete.
- But also, and these are much more common cases: prime `′` and double prime `″`, the correctly typeset foot/minute and inch/second symbols.

I was testing with MacOS VoiceOver, which is all I have available at the moment, and these letters were simply not spoken, so:

- `beſt` became `bet`
- `thou goeſt` became `thou goat`
- `100′` became `100`.

This of course may turn a sentence into utter nonsense.

- `` seems to have a perfect [0% reliability](https://www.powermapper.com/tests/screen-readers/labelling/acronym-abbr-title/) of being spoken, and the first two examples aren’t abbreviations anyway.
- The OTF font feature “historical forms” could be used for the long s. It is all-or-nothing however, so often typographically incorrect (unless one goes to impractical lengths of CSS wizardry), and of course only supported in very few typefaces.

So, what would be the most practical approach to solve this kind of issue, mainly from the perspective of an affected reader?