What is the difference between the Korean language in China and Korean?

First of all I would like to say that these two languages are one language. Because whether it is South Korea or North Korea or the Korean people in China, they are all the same people - the Korean nation.

The difference between the Korean language in China and the Korean language is as follows:

The ancestors of the Korean people in China migrated from the Korean Peninsula, so the language is characterized by their own ancestors. Therefore, there are great differences between the languages of the Korean people in China. For example, in the eastern provinces where there are more Koreans, many Koreans in Heilongjiang came from Gyeongsang-do (nowadays Busan and Daegu in South Korea), and I am a Korean, and my grandfather said that my ancestry is in Gyeongsangbuk-do, so the tone of our speech is more similar to theirs. In the Yanbian generation in Jilin, because they share a border with North Korea, a lot of people have their ancestry from Hamgyeong-do (now North Korea). To our ears, their tone is more humorous.