iamerican-large binary package in Ubuntu Bionic i386

 This package provides the american-large dictionary, based on the americanlrg+
 dictionary supplied with the source for ispell, with additional words added
 from the more comprehensive wamerican-large word list package.
 .
 This is larger dictionary than the one installed by iamerican. Nothing
 prevents you installing both (and others) at the same time.
 .
 There are also -small, -huge, -insane, and standard versions of this
 dictionary, and there are ibritish* packages as well.
 .
 The package also suggests wamerican-large because ispell's (L)ookup
 command needs a word list.

Source package