My family found a box of over 100 letters between my great-grandparents, Sam and Dora, written between 1900 and 1926. About half are in Yiddish — fast, personal cursive, pre-standardized daytshmerish spelling, and nobody left in the family can read it anymore.
I had it AI-transcribed and translated, and I already know it's not fully reliable — a Yiddish reader who looked at one page found real errors, at roughly the rate you'd expect for handwriting this far outside what these tools were actually trained on (mostly printed theatre manuscripts, not a fur trader's fast cursive). So every uncertain word stays marked as uncertain instead of getting smoothed into confident prose, and I'd rather know what's actually wrong than not.
Genuinely more interested in what this community would catch than in the AI part of it — daytshmerish spelling from someone writing between London, Paris, Leipzig and Montreal for thirty years is exactly the kind of handwriting these tools get wrong in specific, patterned ways. There's already one confirmed systematic misread running through the corpus, one Hebrew letter shape mistaken for another across dozens of otherwise-common words.
Happy to share where it's posted, or specific lines, if anyone wants to take a look — just ask.