3. Why does Czech have cases? How are the cases used?

Czech declension is a complex system of grammatically determined modifications of nounsadjectivespronouns and numerals in the Czech language. As with many other Slavic languages, Czech has seven casesnominativegenitivedativeaccusativevocativelocative and instrumental inherited from Proto-Indo-European and Proto-Slavic. This essentially means that a word can have 14 possible forms in singular and plural. Some forms match in more than one place in each paradigm.

Each noun has 7 different cases it can be refered to by. These cases are so standardized that they are often refered to by their ordinal number:

I grabbed WikiPedias descriptions until I write my own summaries.

It helps to understand exactly what subjects, direct objects, and other parts of the language are... Because the noun cases use the different nouns to distinguish exactly the noun as that part of the grammar.

In other words, you can pretty much scramble the order of words in a Czech sentence, and decode what each part is from the case it is written in.
  1. Nominative -- who/what (Person as a Direct Object??): the dictionary form of nou/ adj., pronouns, some nunerals. It expresses the subject of a sentence. (STUDENT je ve škole - The student is at school.)

  2. Genitive -- without whom/what: possesive or partitive meaning ( Kniha STUDENTA - The book of a student)
  3. Dative -- to whom/what: the indirect object in a sentence (Dám dárek STUDENTOVI - I will give a present to the student.)
  4. Accusative -- I see whom/what: the direct object in a sentence (Vidím STUDENTA - I see a student.)
  5. Vocative -- I call (Addressing a person directly): the addressing form (Adame! - Adam!)
  6. Locative -- about whom/what: location (Jsem ve škole - I am at school.)
  7. Instrumental -- with whom/what: the means or instruments by or with which an action is carried out. (Jedu autem - I go by car.)
Case Prepositions used with this case (more on prepositions)
1. nominative no preposition
2. genitive bez - without
blízko - near
do - to, into, until
od - from
okolo / kolem - around, about
u - at, by (location)
vedle - next to
z / ze - from
3. dative k / ke - to, towards
kvůli - because of, due to
navzdor(y) - in spite of, despite
proti / naproti- against
vůči - towards, to, against
4. accusative na - on, onto (direction)
o - for
pro - for
přes - in spite of
za - for, on behalf of, in the course of
5. vocative no preposition
6. locative na - on (location)
o - about
po - after
v / ve - in
7. instrumental mezi - between
nad - above, over
pod - below, under
před - in front of, before
s / se
 - with
za - behind