Nouns

Words are the primary elements that construct a sentence. Each word in a sentence has a different function. Based on its grammatical function, each word is sorted into separate classes, such as nouns, verbs, adjectives, and so forth. Korean has the following word classes.

Nouns

Prenouns (precede a noun, like English demonstratives such as “this,” “that,” “these,” and “those”)

Pronouns

Numbers and counters

Particles (adhere to a noun and indicate grammatical relationships or add special meanings)

Verbs (express action or progress)

Adjectives (describe state or quality)

Copula (like “be verbs” that denote an equational expression: 이다 “be” and 아니다 “be not”)

Adverbs

Korean words are divided into two groups: inflected words and uninflected words. Inflection is the process of adding some kinds of affixes to the original word in order to signal grammatical features such as tense, number, aspect, and person. The addition of an affix alters the form of the original word in the process; however, it does not change its class. For instance, consider how the English word “take” becomes “takes” with the affix “~s” when it is used for a third person singular. Another example is when the verb “learn” modifies its form to “learned” with the affix “~ed.” Notice that these inflected verbs end up carrying supplementary grammatical features (i.e., the third person verb usage and past tense) but their class does not change (i.e., they are still verbs).