The word 'copula' means 'to link' or 'to tie'. A copula is used to say A = B such as 'A is B' or 'Name is Susie'. It originates from the Latin word 'co-apere' meaning 'together + fasten'.

In Korean the copula is '이다' (dictionary form).

이다'am' or 'are' or 'is'

The Korean copula is an adjective '형용사' so it must come at the end of the sentence '문장'. Also it must come after a noun '명사' and must attach to it (no space between).

The sentence ending form of the copula is determined by the speech level.

Formal Polite 합쇼체

NOUN+입니다.

Informal Polite 해요체

Stem ends with a vowel: NOUN+예요.

Stem ends with a consonant: NOUN+이에요.

Intimate 해체

Stem ends with a vowel: NOUN+야.

Stem ends with a consonant: NOUN+이야.

Examples:

Susie '수지' is a girl's name and is a noun which ends in vowel.

Formal Polite: 'I am Susie.' 저는 수지입니다.

Informal Polite: 'I am Susie.' 저는 수지예요.

Intimate: 'I am Susie.' 나는 수지야.

Korean person '한국 사람' is a noun which ends in a consonant.

Formal Polite: 'Susie is Korean person.' 수지는 한국 사람입니다.

Informal Polite: 'Susie is Korean person.' 수지는 한국 사람이에요.

Intimate: 'Susie is Korean person.' 수지는 한국 사람이야.

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NEGATION COPULA

Korean also has a negation copula '아니다' (dictionary form).

아니다'am not' or 'are not' or 'is not'

The Korean negation copula comes after the noun and MUST have a space between.

The sentence ending form of the negation copula is determined by the speech level.

Formal Polite 합쇼체

NOUN 아닙니다.

Informal Polite 해요체

NOUN 아니에요.

Intimate 해체

NOUN 아니야.

Examples:

Formal Polite: 'I am not Susie.' 저는 수지가 아닙니다.

Informal Polite: 'I am not Susie.' 저는 수지가 아니에요.

Intimate: 'I am not Susie.' 나는 수지가 아니야.

Formal Polite: 'Susie is not Korean person.' 수지는 한국 사람이 아닙니다.

Informal Polite: 'Susie is not Korean person.' 수지는 한국 사람이 아니에요.

Intimate: 'Susie is not Korean person.' 수지는 한국 사람이 아니야.

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EXPRESSING EXISTENCE, LOCATION OR POSSESSION

In English the copula has more uses than the Korean '이다' and '아니다'. For example the Korean copulas can't be used to say 'have' or 'exists'. Instead Korean has special adjectives for that purpose:

있다'to exist' or 'to have' (dictionary form)

없다'to not exist' or 'to not have' (dictionary form)