My KOEHLI/KOHLI/KAHLEY family also hails from Bern Switzerland. I know the "O" had umlauts and was sometimes "Anglicized" to either an "O" only or an "OE" combo. Later they family changed the name to KAHLEY.
My great grandmother was Anna Margarete KAHLEY (b:1863 Moline, IL d:1903 Ayreshire, IA), and her father was Friedrich Wilhelm KOEHLI (b:1825 Kallnach, Bern CH d:1883 (Maquoketa/Smithtown, IA). He is said to have been a Dairy Farmer in Switzerland.