I’ve been confused about this.
Does the last name “Koch” have all these possible pronunciations?:
Coke
Cotch
Cock
Cook
???
And the German one, which is like “ko[kh]” with the [kh] representing an “h” like sound, like the “h” in “loch.”
If we’re talking about the billionnaires, the underwriting announcements on PBS pronounced the name as “Coke”.
Have a coworker who was de-cock in South Africa but de-cotch when he was in the US.
Spelled “de Koch” of course.
He was ridiculously popular with the ladies, some of whom refused to use his preferred stateside pronunciation.
I suspect it is issues like these that cause the pronunciation variations outside the Duetchesphere.
The Koch I worked for preferred “Cook”.
They have a refinery near my old home. It’s always pronounced “Coke” hereabouts.
Regards,
Shodan
And, of course, the former NY Mayor, Ed Koch, was pronounced “Cotch.” So, yes, “Koch” has all those pronunciations, plus at least the German one. As to how you know which way to pronounce it when you see it? You don’t really. You have to ask what the pronunciation is. And, sometimes, even then it’s not the same as the family pronunciation. AFAIK, Dick Cheney and his family pronounce his name “ChEE-nee,” but the media pronounces it “CHAY-nee,” for example.
The one I knew pronounced it like “coach.”
There are other German last names that also have multiple pronunciations in the U.S. My mother’s maiden name is “Roth”. Nearly everyone else in the U.S. pronounces it with a short “o”, but her family pronounces it with a long “o”. I was going to say that nobody other than her family pronounces it that way, but I just did a search on the phrase "Roth pronounced with a long ", and I found this article, which isn’t (as far as I know) about a close relative of mine:
http://newspaperarchive.com/us/kansas/salina/salina-journal/1982/04-18/page-2
A handy way to remember this that somebody posted here once: “I’d like to buy the world.” - A Koch
That makes some sense, as in the German, it would be pronounced something like “rote.” Same happens with the Hungarian surname “Tóth/Toth” It’s pretty much “tote” in Hungarian, but in English, it can be pronounced to rhyme with “both” or “boat,” depending on how insistent the family is about preserving the original pronunciation as much as possible.
My physics teacher, Mr. Koch, pronounced his last name as Cotch, as to rhyme with scotch. He was actually from Germany, but came to the US at age five.*
- When he mentioned this we asked him if he still remembered how to speak any German, and he said yes, rattling off a sentence. Most impressed, we asked what it meant. He turned pink and admitted he’d just said “I’d like some chocolate milk”
The “cook” pronunciation also has the charm that it provides a literal translation of the word’s meaning in German, but I guess this is of only secondary concern to most Kochs.
My father worked for an oil company in the 1920’s and 30’s owned by the Koch family. I always heard him pronounce it “Coke”.
If TPTB will forgive a minor tangent, I was stationed on an island where the big town was named “Cockburn”, which always struck me as a good name for a place where you’d want to be VERY careful about contracting an STD. They pronounced it “Coh-burn”
Customers will ask for “Cotch” I correct them, He spells it that way, but he says “Cook.”
The owner of Holiday World amusement park pronounces it “Cook”.
The former mayor of New York pronounced it “Cotch”.
I like the first for lots and lots of reasons. Just in case RavenMaven ever reads the Dope.
Guh-doff-ee.
I had a friend who pronounced it (her last name) as Kah.
Cosh.
Your location says Milky Way Galaxy. Where was your old home? 
Another statistic for “Cook”: Kid in my Junior High (1963-1966) class was Koch and pronounced it Cook.