This Python script converts text to use the archaic long S letter ( ſ ) in its spellings.

English, Spanish, French, Italian, and German are supported.

import long_s

print(long_s.convert("The discussion was surprisingly insightful.", lang="en"))
print(long_s.convert("La discusión fue sorprendentemente perspicaz.", lang="es"))
print(long_s.convert("La discussion était étonnamment perspicace.", lang="fr"))
print(long_s.convert("La discussione è stata sorprendentemente perspicace.", lang="it"))
print(long_s.convert("Die Diskussion war überraschend aufschlussreich.", lang="de"))

The diſcuſſion was ſurpriſingly inſightful.
La diſcuſión fue ſorprendentemente perſpicaz.
La diſcuſſion était étonnamment perſpicace.
La diſcuſſione è ſtata ſorprendentemente perſpicace.
Die Diskuſſion war überraſchend aufſchluſsreich.

With German words, the script might encounter an occurrence of the letter S that remains ambiguous, even after the conversion process.

By default, any leftover ambiguous S will be replaced with a long S ( ſ ).

If it's preferred to leave it up to human interpretation, the program can be explicitly told to leave these ambiguities marked in the returned string:

print(long_s.convert("Mäuschen", lang="de", keep_unknown_s=True))

This will print Mäu╳chen, which can then be manually changed to Mäuschen.

Thank you Andrew West of the TeX Users Group for the documentation found under The Rules for Long S, which was fundamental in writing the conversion functions for English, Spanish, French, and Italian.