In English, order of the words is important to convey the meaning of what you are trying to say. If you use incorrect ordering of the words in English, you may convey a meaning that is completely different from what you had originally intended, or the sentence might be wrong completely. For example, if you say

My children always bite my dogs.

While the above sentence is grammatically correct, it may not actually be what you wanted to say. You have to put the words in their correct positions to convey what you mean because the words in a sentence perform different functions. Below is what you probably meant to say (unless you have really weird children).

My dogs always bite my children.

Now that sounds more correct! My dogs is the subject of the sentence. And my children is the object of the action bite. In English, the relations between the words in a sentence can also be expressed by prepositions.

The letter was written to Chris.

Chris. The letter was written by Chris.

In the Russian language, we use cases to express these types of relations. A case shows what function a word carries in a sentence. Nouns, adjectives, pronouns, numbers, and other part of speeches can have their own declinations, changing their endings. Each case has its own set of endings.

For example

The letter was written to Chris - Письмо было написано Крису

Chris - Письмо было написано Крису The letter was written by Chris - Письмо было написано Крисом

Крис is the stem, -у and -ом are endings.

There are six cases in Russian: Nominative, Genitive, Dative, Accusative, Instrumental, and Prepositional.

Nominative

The nomative form is a dictionary form and expresses the subject and the predicate.

The subject - Наталья много работает.

много работает. The predicate - Она учительница.

Accusative

The accusative form is used to express the direct object of a transitive verb, the direction of motion, and the duration of an action.

Direct object of a transitive verb.

Что он читает? - What is he reading?

- What is he reading? Он читает новую книгу. - He is reading a book.

Direction of motion.

Куда он идёт? - Where is he going?

он идёт? - Where is he going? Он идёт в школу. - He is going to school.

Duration of an action.

Ты давно изучаешь русский? - How long have you been studying Russian?

- How long have you been studying Russian? Только ещё неделю. - Just a week.

Prepositional

The prepositional defines the location, the object of speech or thought, and the time.

Location

Где он живёт? - Where does he live?

Он живёт в Москве. - He lives in Moscow.

The object of speech or thought

О чём он говорит? - What is he talking about?

Он говорит о работе. - He is talking about the job.

Time

Когда ты был в Москве? - When were you in Moscow?

Я был там в прошлом году в январе. - I was in Moscow in January last year.

Genetive

The genetive form expresses the possession, the measurement and quantity, and the absence.

Possession

Чьи это документы? - Whose documents are these?

Это документы Наташи. - These are Natasha’s documents.

Measurement and quantity

У тебя большая семья? - Is your family big?

У меня 3 брата и 2 сестры. - I have 3 brothers and 2 sisters.

Absence

У тебя нет ручки? - Do you happen to have a pen?

- Do you happen to have a pen? Нет, у меня нет. - No, I don’t.

Dative

The dative form is the recipient of an action, the age, and a certain state or condition of a person or an object in impersonal sentences.

Recipient of an action

Кому вы звоните? - Whom are you calling?

вы звоните? - Whom are you calling? Я звоню Антону. - I am calling Anton.

Age

Сколько ему лет? - How old is he?

лет? - How old is he? Роберту уже 20 лет. - Robert is already 20.

Certain state or condition of a person or an object in impersonal sentences

Вам трудно понимать меня, когда я говорю по - русски? - Is it difficult for you to understand me, when I speak Russian?

Мне нет, а вот Ивану очень трудно. - No, it’s not difficult for me, but it’s difficult for Ivan.

Instrumental

The instrumental case shows the instrument of action, the joint action, and the profession, and the place.

Instrument of action

Чем ты любишь писать? - What do you like to write with?

ты любишь писать? - What do you like to write with? Ручкой , а ты? - With a pen, and you?

, а ты? - With a pen, and you? А я карандашом. - With a pencil.

Joint action

C кем ты был вчера вечером? - Who were you last night with?

ты был вчера вечером? - Who were you last night with? С подругой. - With my girlfriend.

Profession

Кем ты работаешь? - What do you do?

ты работаешь? - What do you do? Менеджером. - I am a manager.

Place