The language family of Korean is called Koreanic and it consists of mainland Korean plus the dialect on Jeju island. Of course, there are many dialects in Korean, and Jeju is the most significantly different.
The Korean taught in classrooms and used by Koreans today was formed hundreds of years ago, and before that, older versions of the language were used.
Korean is the official language in both North Korea and South Korea, and North Korea is called DPKR (Democratic People’s Republic of Korea), while South Korea is known as ROK (Republic of Korea). Korean is also the official language of the Yanbian region of China.
When you realize that Korean is spoken by more than 75 million people worldwide, you can see the necessity of Korean document translation services for so many industries.