Greetings!

My great-grandfather Joseph Sunlin (born 1855 in Ohio) Identified his father as "Adolph Sunlin". His mother, Elizabeth is recorded as having been born in Germany, and her husband was recorded as "Deabould Sunlin". Same guy maybe?

Louis F. Sunlin (b 1858 also in Ohio) a cousin or brother? recorded his father as having come from Alsace, France and his mother from Baden, Germany.

I have found many entries for Sunlin or Sünlin in Wurttemberg around the 16th century. But there are no Sunlins in any German phonebooks.

I have observed the etymology:
“OHG. –lin: sünlin ‘little son’, schtflin; in the modern –lein (scherflein &c.) and in the Swabian –le the effect of the I is obliterated, but in Swiss –li (büebli, füessli &c.) it is still a living force.”
-Selected Writings of Otto Jespersen (Routledge Revivals); Otto Jespersen. Routledge, Mar 17, 2010

The nearest I can find in Germany is Söhnlein, but they are not centered around Wurttemberg. An alternate spelling is Soehnlin and this shows up a lot in the Alsace-Lorraine/Haut Rhin region.

Any ideas?