I'm not sure if Old English counts here, but I can't find the answer to this anywhere.
How would one pronounce gemænscipe? I believe it's Old English for "community".
I would pronounce it as gə'mænʃipə. No one is absolutely sure about the pronunciation of Old English. Whether you pronounce g as /g/ or as /j/ is a problem as the change of /g/ to /j/ did not begin with a stroke of the bell in a certain year and in all regions at the same time. So it is a little bit up to you how you pronounce it.
Yes, gemænscipe is the Old English word for Latin communitate(m), nominative communitas meaning community. The Old English word has almost the same form as modern German Gemeinschaft. (I have to look up the word in Low German, it should almost be similar to the Old English form.)
Low German has a lot of slightly different regional variants. The most frequent form is Gemeenschop.