Many languages have noun cases. English … kind of does, but they aren’t nearly as significant, so we don’t teach them. Or, I suppose, we have something that somewhat reflect cases, but we don’t call them cases. Anyway, there are definitely some correlations between cases in other languages and English grammar.
While we tend to ignore cases in English classes, maybe it would be a good idea to acknowledge some of the cases used in the students’ native language(s) and explain what English uses instead.
In many languages, nouns undergo declension to reflect whatever case they’re in, which simply means their forms alter slightly. In English, this doesn’t happen to nouns, but it does happen to personal pronouns.
Subject Pronouns correspond to the NOMINATIVE case and take the forms of I, you, she, he, it, we, you, they, and who.
Possessive Pronouns correspond to the GENITIVE case and take the forms of my, your, her, his, its, our, your, their, and whose when they precede the possessed noun, and the forms of mine, yours, hers, his, it, ours, yours, theirs, and whose when they follow to be or ‘of’.
Object Pronouns correspond to every other case (except VOCATIVE) including the ACCUSATIVE, DATIVE, LOCATIVE, INSTRUMENTAL, and ABLATIVE cases. They take the forms of me, you, her, him, it, us, you, them, and whom.
You is the only personal pronoun used to address someone, which corresponds to the VOCATIVE case. What makes this unique is that it is sometimes “understood” (or replaced by a ‘null’ pronoun). In imperative sentences, for example, you often wouldn’t say or write ‘You’, although the meaning is still there.
Because of the declensions, personal pronouns (less than 40 words) behave a little differently from every other word in the English language. If students are thrown off by this, it may help to explain that pronouns have cases.
While English nouns do not change form based on case, they are preceded by prepositions for all ‘Object’ cases, except sometimes Accusative or Dative. The prepositions used depend on the case.
ACCUSATIVE – for
DATIVE – to
GENITIVE – of
LOCATIVE – prepositions of static time or place, such as at, in, on, etc.
INSTRUMENTAL – prepositions of function, such as by, with, via, and through
The Ablative and other cases may depend on the specifics of the students’ native tongues, but there’s a good chance that English has some pronouns that could match them.
The cases expressed here are common throughout several languages, but your students’ native language(s) may be missing some of these, may have more, or may have different specifics. You’ll need to learn about the relevant language(s) before teaching how cases transition into English.