(non-native speaker)
Is there a reason why the English language has “special” words for a specific topic, like related to court (plaintiff, defendant, warrant, litigation), elections/voting (snap election, casting a ballot)?
And in other cases seems lazy, like firefighter, firetruck, homelessness (my favorite), mother-in-law, newspaper.
A quick “rule” is to see how old the word/concept is. “plaintiff” would have existed almost as long as the English legal system came into being, or probably even older to the court of Assizes pre-12th century.
Whereas firefighter as a profession might have only become a word after the establishment of fire departments by insurance companies, which I think might have been a 19th century development.