Greetings,
I am researching my DITTMAR line in America. When the family pronounced the name they said DITTMER. The name is always written with an "a" though. This is the most elusive line I have to trace, very - very difficult. My Peter Freidrich Dittmar was from Nassau, Hannover, Prussia and married a PRITZ. I have Friedrich's and Henrich - Henry's everywhere in the naming pattern so I think we may have a connection if you want to explore it further with me. Like you, I haven't found much help at familysearch.org either. I have big gaps to fill, its a frustrating line for sure.
Sincerely,
Kelly Barnett