I grew up a Kienlen. Usually, I had to tell people more than once how to spell it - two Es and one I? - or is it the other way? I believe my ancestors had to do the same thing. It was often misspelled in newspapers and on documents - Kinlin, Kinlen, Kienlin, Kenlin, etc. My immigrant ancestor spelled it Kienlen, just as it had been spelled on his German Christening record in 1799. His uncle who immigrated to the UK also spelled it Kienlen, but the family later changed it to something "less German" during WWII.
There is a Kienlen Avenue in St. Louis, in Wellston. This road and the surrounding property used to belong to Christian Kienlen, my 3rd great grandfather. My dad said the street used to be the driveway to the family home - a large brick home with (according to my dad) stone lions guarding the entrance. Now it is primarily lined with businesses. I'm pretty sure the business owners get tired of spelling their street address for people, but since my sisters and I were the last of the Kienlens, at least the name exists somewhere.
How to pronounce Kienlen is a whole other issue. We always said Kienlen like "Kenlin", the pronunciation being passed down through the generations as these things usually are. No one else ever said it that way. It was always "Keenlin" or "Kinelin". Again, we would have to correct people. One day in 2007, my sisters and I were with my dad. He told someone that his last name was pronounced "Keenlin". We questioned him, of course, and he said someone told him it was supposed to be pronounced "Keenlin". We had a good laugh about that and, naturally, still say "Kenlin." After all, that's how we learned it, and you should never change how you say (or spell) your name based on the opinion of a stranger!