They're wonderful. They're obscure. They're often quite pointless.
White House Reporter asks after 'assertations'
Assertation, the little-beloved (and even less used) younger brother of assertion, had a brief and shining moment in the sun on the 25th of April, 2017, when it was employed by a reporter at the White House press conference.
In the ensuing mayhem many people rushed to the dictionary to see if the word was in fact a real word, or if the English language was once again under attack by fifth columnists.
A reporter in today's #WhiteHous #PressBriefing used the word "assertation" #NotAWord
— Padma 4.0 (@Padma4Point0) April 25, 2017
#itisdefinitelyaword
Assertation means much the same thing as assertion, but takes slightly longer to say or write. It has an extra syllable in it, which annoys many people (much like preventative). The word has been in extremely limited use since the early 17th century.
What, believe his vain assertations, before the demonstration of my senses? No, no; my Love's not so blind.
—George Farquhar, Love and a Bottle, 1699