MORPHOLOGY: a term used for the unbounded list of potential words,
where 'potential word' is defined as any word form that can be generated by
the word formation rules of a language. Hence, the potential lexicon contains
the actual or attested words plus the potential, but not attested words.
EXAMPLE: in English, the potential lexicon contains actual words such as
approve, approval, recite, recital, derive, and describe, and
the potential words *derival and *describal.