Post by Marco MoockPost by Aidan KehoeA grammar book for the relevant language. Wiktionary can be some help
too. If you want specific recommendations you’ll need to be more
specific about the language(s) you’re interest in.
I am looking for an online tool for the English language.
For English nouns the rules are simple. Nominative, accusative and
dative are identical. For the plural, add an "s", although there are
some (not many) irregular plurals.
For genitive, add "'s" in the singular and "s'" in the plural.
For personal pronouns you just have to memorise the inflected forms.
Luckily there aren't many pronouns. For non-personal pronouns like
"everyone", just treat them like nouns.
English adjectives don't inflect for case.
Hundreds of years ago the rules were more like German, but over the
years most of the case endings disappeared. (As they probably will, I
suspect, in German.) As a result, grammarians have largely stopped
talking about grammatical case in English. Even the genitive is now
called the possessive (which I find misleading, because it doesn't
necessarily indicate possession) by most people.
For English verbs, a good starting point is
https://conjugator.reverso.net/conjugation-english.html
--
Peter Moylan ***@pmoylan.org http://www.pmoylan.org
Newcastle, NSW