I haven’t had the time to study these sort of things even if it’s something that i am passionate about but Grimm’s tales were published about 150 years ago. I remember when I started out here on Lingq I used to read Sherlock Holmes in German as a cost effective way.
I did ask a few questions on the forums and the general consensus was that it was a very bad idea as the words that I asked about were really old fashioned. There are of course a few things to consider when analyzing this.
- Every book that is of a certain age no matter what language will have outdated speech, I sure.
- I used the original copyright free ones that you can download from the likes of Gutenburg/Librivox. I am sure that the modern editions use a modernised language.
Still one thing that I do know about German spelling then vs now is that whereas some words have a t today they used to have th. These popped up a lot in the Sherlock Holmes book that I read.