Personal pronouns
I, me, you, he, her, them are called personal pronouns, because they cover the full range of grammatical persons:
the first person (I, we)
the second person (you)
the third person (he her them).
Personal pronouns are almost the only place in English grammar where 'case' is relevant.
In languages such as German, several of the words in a noun phrase have distinct inflections to show the phrase's grammatical function in the sentence - for example, whether it is being used as the subject or object of a verb.
In English, only the personal pronouns have different forms or cases which show whether they are subjects or object