In Korean, the nouns are typically marked by particles, with no corresponding English equivalent. There are two types, the case and the special particles.

Case particles - indicate the syntactic role of the noun they are attached to, whether the subject is a subject, an object, direct object, etc.

Subject particle 이/가
이 for consonant ending nouns
가 for the vowel ending nouns

When in negation(with negative predicates), the noun with the particle is not the subject of the sentence, but rather, part of the predicate. Consider this sentence.

나는 한국 사람이 아닙니다. As for me, [I] am not Korean [person].

The subject case particle can also be used in many nouns in on sentence. It is called double-subject construction, although it is not that the sentence has two subjects. The focus of the sentence is contextual. For example:

잭슨이 허벅 다리가 크다. Jackson's thighs are big.

In this sentence, the focus is not on Jackson, but his thighs. If you already have ideas and knowledge about Korean language, you might notice that 잭슨이 can be changed to 잭슨의, using the possessive case particle 의, which is correct. However, the use of 이 is also grammatically correct. In colloquial conversations, particles are usually omitted.

Direct object particle 을/를

을 for consonant endings
를 for vowel endings

Direct object particle is attached to the n