In standard English, for example, you can say I am or it is, but not “I am” or “it is.” This is because the grammar of the language requires that the verb and its subject coincide personally. The pronouns I and him are respectively the first and third person, just as the verbs are and are. The verbage form must be chosen in such a way as to have the same person as the subject, unlike the fictitious agreement based on meaning.   In American English, for example, the expression of the United Nations is treated as singular for the purposes of concordance, although it is formally plural. There is also unanimity in the number. For example: Vitabu viwili vitatosha (Two books will suffice), Michungwa miwili itatosha (Two orange trees will suffice), Machungwa mawili yatatosha (Two oranges will suffice). Modern Turkish has six cases (in Turkish`smin helleri). Modern English doesn`t have much correspondence, although it`s there. Although not important in modern English, the cases were much more clearly revealed in ancient English and other ancient Indo-European languages, such as Latin, Persian, Ancient Greek and Sanskrit. Historically, Indo-European languages had eight morphological cases, although modern languages are generally fewer, with prepositions and series of words, to convey information that had previously been transmitted with different nomic forms.
Among modern languages, cases are still important in most Balto-Slavic languages (except Macedonian and Bulgarian), most have six to eight cases, as well as Icelandic, German and modern Greek, which have four. In German, cases are usually marked on articles and adjectives, less on nouns. In Icelandic, articles, adjectives, people`s names and names are marked in case, among other things, the living Germanic language, which might resemble the most protogermanic. Modern English has largely abandoned the flexible and European case system in favour of analytical constructions. The personal pronouns of modern English keep the morphological case stronger than any other class of words (a remnant of the larger fall system of ancient English). For other pronouns and all names, adjectives and articles, the grammatical function is indicated only in order of words, prepositions and by the “Saxon genius” (-s). [a] It is widely accepted that the ancient Greeks had some idea of the forms of a name in their own language. A fragment of Anacreon seems to prove it. Nevertheless, it cannot be inferred that the ancient Greeks really knew what grammatical cases were. Grammatical cases were first recognized by the Stoics and some philosophers of the eventual school.   The progress of these philosophers was then established by the philologists of the Alexandria school.   In total, the pronouns of English staff will generally have three morphological cases: in some cases, in Swedish, Norwegian and Danish, adjectives and participation as a predicate do not seem to agree with their subjects.
This phenomenon is called pancake phrases. Languages cannot have a conventional agreement at all, as in Japanese or Malay; barely one, as in English; a small amount, as in spoken French; a moderate amount, such as in Greek or Latin; or a large quantity, as in Swahili. For similar reasons, the usual order of the four cases in Iceland is nominal – accusatory – from a genetic point of view – as shown below: this is not always the case, or even the standard for Australian languages.