This is a hoot. It begins:

Several weeks ago, we sent you a list of translations of the German markings in the Mahler [Symphony #1]. We now realize that this list contained many serious errors. These sheets contain the correct versions. So we don’t waste valuable rehearsal time on this, copy these corrections into your part immediately.
GERMAN – ENGLISH
Langsam – Slowly
Schleppend – Slowly
Dampfer auf – Slowly
Mit Dampfer – Slowly
Allmahlich in das Hauptzeitmass ubergehen – Do not look at the conductor

There’s more. Funny stuff.