There is also another aspect on it all.
1. English is not the problem, as for a native German it is an easy to
learn language, if you are not willing to use such an elaborated English
like Charles Dickens did. But elder people, who are warmly welcome in
this list, because they often know about things apart from only dates
and names, often have difficulties with English or are even not able to
understand it. Moreover the documents that you are looking are written
in that German.
2. Why should WE speak English? There were times when scientists studied
German to be able to read the most important publications in their
discipline. That is just 100 years ago, and was over with the First
World War. YOUR ancestors turned their backs to their fatherlands and
even fought as soldiers against Germans, and even if it was only to
proove that they were true Americans, like in Philadelphia where still
today US uniforms worn by them are exposed in local museums.
You won those wars, therefore you now have the ability to declare what
was wrong and who was right, because in the end of all doubts justice is
just bound to power and not to philosophy. I mean: the winner writes the
history books. You destroyed Prussia, let East Prussia be divided by a
ballpoint pen line (that's how it was made on a rough map in Yalta) and
let it be exploited in any means so that there is hardly anything to
find today, you Americans even yourself exploited Germany (e.g. look
into the Washington's galleries) while we today are searching in the
remnants of East Prussia and our Prussian culture. And now we shall
speak your language?
We are friendly enough when we answer English questions, and that is
what has always been done here.
Mit freundlichen Grüßen