But isn't Korea a peninsula? "Korea" is not a country. The languages are not called "Northkorean" or Southkorean". Rather just Korean named after the still united country of Korea.
Korean is a language and Korea is a peninsula made up of two countries. Such a language as North Korean doesn't exist, just like how East German was never a language.
Okay, just ignore Cambodia. Its population is not that high. Also, I was so surprised to learn that more people speak Uzbek than Kazakh. I had believed that Kazakhstan is the biggest among those 5 ex-USSR-stans for all time!
Chinese/China(900 mil speakers)
Persian/Persian(historic name for iran)(54 mil. speakers)