Install iamerican-insane by entering the following commands in the terminal:
sudo apt update sudo apt install iamerican-insane
Description:
American English dictionary for ispell (insane version)
This package provides the american-insane dictionary, based on the americanxlg+ dictionary supplied with the source for ispell, with additional words added from the more comprehensive wamerican-insane word list package. . This is an even larger dictionary than the one installed by iamerican-huge, and possibly contains invalid words (as well as words that are very uncommon). Nothing prevents you installing both (and others) at the same time. . There are also -small, -large, -huge, and standard versions of this dictionary, and there are ibritish* packages as well. . The package also suggests wamerican-huge because ispell's (L)ookup command needs a word list.
Homepage: http://www.lasr.cs.ucla.edu/geoff/ispell.html
Version: 3.4.00-6
Section: universe/text