I have found no way of writing the pronunciation of my name on Facebook.
The only option I get is their default, which is wrong. "DAY-vid" is fine. But my last name has TWO Ms in it. You don't pronounce it "SI-mer"... it's more like "SIM-mer." So I just turn the pronunciation off because it annoys me greatly...
I've always thought that my name was kinda a no-brainer to pronounce... "Summer" with an "I" instead of a "U" is close enough because people who are not me won't catch the missing "M" and I don't care if somebody is giving it a shot. But SO MANY TIMES I get "Summer" or "Zimmer" or "Sighmer" or "Simner" or "Simmey" and whatnot. Which, no big deal, because it's easy enough to say my name back to them... but to this day I don't know where those pronunciations come from. I can only guess that they have people in their life that are close and seeing what they know? In any event, Facebook isn't helping.
My name is from the Frisian word for "summer" and it's not generally all run together when I've heard it. It's got a subtle double-tap on the M in there. So that's how I've always pronounced it. Not sure about my family, but I don't really care because it's my name and I know the origin.