The accusative case is used when an object receives the action of a verb. In English this is seen as the word I changing into the word me when used in the sentence, The government likes me (Note that I turns into me in other cases too, but this is the most common.)

For back-vowel words, the ending is -t or -ot.

Én szeretem a lakásot I like the apartment.

For front-vowel words, the ending is -t or -et or -öt.

Én szeretem azt az embert I like that person.
Én szeretem a nőt I like the woman. Note lack of link vowel.
Én szeretem a hegyet. I like the mountain.
Én szeretem azt a hegyet. I like that mountain.

For words ending in a short vowel except i, lengthen this.

Macska cat
Én szeretem a macskát I like the cat. Note how trailing vowel is lengthened.

The accusative case is the last to be applied, after plurals and possession, etc.
When the accusative case is applied after other cases, the range of link vowels is reduced to just two: -at for back-vowel words -et for front-vowel words

Én szeretem a lakást I like the apartment.
Én szeretem a lakásokat I like the apartments.
Én szeretem az nőket I like the women. Note how now the link vowel is e.
Én szeretem azokat a hegyeket. I like those mountains.

Some nouns change their stem when they are put into the accusative.

eper strawberry.
Én szeretem a epret I like the strawberry. Note the dropped e from the strem.

Any noun receiving the action of a verb must be put into the accusative case, including personal and demonstrative pronouns and proper nouns.

Ági nem szeret engem Ági doesn't like me. Note indefinite conjugation.
Daniel szereti azt Daniel likes that (Daniel likes it).
Én szeretem Ágit I like Ági.
Én szeretem Londont I like London.

It is common to see proper nouns and acronyms written this:

Hasznaljunk MSN-t Let's use MSN.

We also apply -t in answers to questions when the object is given but theverb and subject are omitted.

• Akarom azt. I want that.
• Ezt? This?
• Nem, azt. No, that.
• Az almát? The apple?
• Igen. Yes.

This is simply short-hand for:

• Akarom azt. I want that.
• Akarod ezt? You want this?
• Nem, akarom azt. No, I want that.
• Akarod az almát. You want the apple?
• Igen. Yes.

See also the sections on interrogative and demonstrative pronouns.