This question contains some speculation that a good answer would confirm or deny:
The North Korean government recently released a statement that referred to Donald Trump, the current US president, as a "dotard", meaning a senile old man. This is a fairly rare word in the English language, one that human translators would not usually use due to its obscurity.
One of the few places in modern English prose where this word occurs in the book The Two Towers by J.R.R. Tolkien. It is used by the wizard Saruman when he is trapped in the tower of Orthanc after the siege of Isengard. The exact quote is: "Dotard! What is the house of Eorl but a thatched barn where brigands drink in the reek, and their brats roll on the floor among the dogs?" It's is also used by the steward Dentheor in the Tolkien book Return of the King: "My son, your father is old but not yet dotard."
Tolkien's Lord of the Rings series has been translated into many languages over the years including into Korean. One of the most commonly used translation softwares at the current time is Google Translate. It largely uses statistical machine translation. In contrast to other machine translation techniques that try to build a syntax tree, it instead uses bilingual text corpora, in other words, texts that exist in two languages to statistically match up corresponding words and phrases.
All of this leads me to the following hypothesis that I cannot prove, due to my lack of knowledge of Korean: that the North Korean government may have fed their statement about Donald Trump through Google Translate or similar statistical translation software, and with suprising accuracy, it translated the Korean word "neukdari" into English "dotard" based on the words being used as equivalents in the Lord of the Rings books.
One straightforward way to partially substantiate this hypothesis would be to see what word is used in place of "dotard" in the Korean editions of the Lord of the Rings books. This is beyond my abilities, but may be practical for someone to do. Another way to see if this works is to try a practical test of Google Translate from Korean. While we may not be able to see what specific texts Google uses to drive it's software, these could be strong circumstantial evidence that the hypothesis may be true. There may also be other ways of probing this question that other people may think of. I would be interested to hear of those and of any evidence that can be brought to bear.