For smaller languages the steps would be: - Somebody would have to digitize an old book without mistakes. - Somebody would have to publish it online. - Somebody would have to scrape and archive that. - Somebody would have to transliterate it to Latin script. - That transliteration would also have be the same transliteration I'm using.
It's unlikely it will be done for a lot of languages.
There's easier schemes that don't rely on that.
Remembering random words is hard. This is how we got into this in the first place.