I originally thought Kerry was trying to pronounce it with some ‘elitist’ formal pronunciation...
It took a while before I realized he was just too stupid to know who Genghis Kahn was.
In Mongolia it is written and pronounced Chinggas Khaan.
The airport in the capital of Mongolia, Ulaanbaatar, is the Chinggis Khaan International Airport.
https://en.m.wikipedia.org/wiki/Chinggis_Khaan_International_Airport
The main square in the city is the Chinggis Khaan Square.
I saw this on a Josh Gates show and did some internet digging. It pained me to find that Teresa Hienz’s gigolo actually got something right.
I’m still scarred from the experience.