With a text file, e.g. a word file of a story, following https://superuser.com/a/1598832/109367 , a list of all distinct words could be generated.
However, this is not yet a words of the original form -- for verbs (e.g. go), there are gerund, conjugations, third-person singular verb (going, goes, went, gone); for nouns (e.g. apple) there are plural forms (apples).
How could I get the original form of a word? so that I could get a vocabulary list of a book etc.
Even better, if this solution is applicable to not only English, but also, such as French etc.