Are there any new words in common usage for things that existed 200 years ago?

Solution 1:

There are many dialect words that have fallen into disuse; some may have been replaced by newer words and some not.

For one word that is rich in historical and social change, look at the changing names for privy / lavatory / toilet.

Another example is the changing role of science:

Scientists had previously been known as natural philosophers, but a new emphasis on empirical and inductive methodology led to a perceived need for change:

1840 WHEWELL Philos. Induct. Sci. I. Introd. 113 We need very much a name to describe a cultivator of science in general. I should incline to call him a Scientist.

https://public.oed.com/blog/nineteenth-century-english-an-overview/#a-changing-language-grammar-and-new-words

For examples of dialect words not used now see

https://www.mentalfloss.com/article/59924/50-old-british-dialect-words-incorporate-conversation

Solution 2:

Not to be political but how about the word dotard? I am curious as to how that word came to be used by North Korea and what the persons English language background is. My guess is that it’s an old English word and they used a thesaurus when writing the letter.