Just because there's a post office doesn't mean there's a town in this little corner of the world. The gazeteer that the other genealogist recommended you look at shows where Langberg was...I don't remember it being anything more than "Langberg Country School" & "Langberg Post Office" - all in Langberg Township, but not next to each other at all. Rhame, Bowman ND, & Ludlow, Buffalo SD were the villages.
The people of Langberg township developed the idea of a township meeting where all citizens could speak about the township problems, but I don't beleive your ancestors were involved as officials in the first of these meetings. Again, Prairie Tales I, page 422 describes this area. It's a wonderful homeland. Deanna