Assuming it is Langnau im Emmental, my husband has family history there and is nearby Steffisburg.
We visited both (by train) on a day trip from our hotel in Mürren.
We had an address ( actually two) for the family home in Steffisburg, and hired a cab to take us there from the Steffisburg train station. On the way, I sat in the front and told the taxi driver of my husband’s Swiss connection. She exclaimed, “So you have Swiss blood!” And I responded in my best German (not Swiss German) , “No, my husband has the Swiss blood, but I have a Swiss heart.” She had trouble finding the address (it was ambiguous) and quickly shut the meter off. When we finally found it, we learned that the property had been given to the community by the last family member to own it, a childless bachelor brewmaster. It was used as event space, and they were having a special exhibition of the architectural and decorative details of the building and brewery. We were given a private tour and I understood maybe 1/2 of the narrative which was in Swiss German. But it was fun, and we brought home a nice poster with the family name on it.
Then we went to Langnau I.E. to have lunch at the Bären. The building was formerly the clinic of “Wunderdoktor” Micheli Schüppach, who counted Goethe among his patients. This doctor was a great-great ( and maybe more “greats” uncle of my husband. You can read a brief history of the restaurant here:
http://www.baerenlangnau.ch/
We sat on the deck next to a huge flower basket that was visited repeatedly by what looked to be impossibly tiny hummingbirds. Turns out they were moths, commonly called “hummingbird hawk moths”. I have only seen them once since, visiting a flower basket at a mountain restaurant outside Chamonix.
Anyway our “roots trip” day was lots of fun. I highly recommend tracking down all leads; you never know what you might find.