1. Complementation

2. Complementation
A linguistic phenomenon wherein the syntactic head of a phrasal category licenses a word, a phrase or a clause to complete its meaning.
The complement completes the action of the verb, and hence cannot be dropped off COMPLETE IDEA = HEAD + COMPLEMENT The girl hit [the boy] Flowers are [very beautiful] COMPLEMENTATION = COMPLEMENTIZER = COMPLEMENT

3. Complements are licensed by their heads
Complements are licensed by their heads. In order to complete the meaning of the phrase of sentence, a complement is required from the head in a phrase.
Absence of the complement generates ungrammaticality and unacceptability because the syntactic head is, in itself, unable to express its complete meaning.
Complements are different from modifiers in that the latter change semantic properties of the phrases ENRICHED COMPLETE IDEA = HEAD + MODIFIER

4. Complements
A noun complement is the complement of the subject (Noun/Pronoun) of a sentence. It describes the subject and follows a linking verb She is [beautiful] (adjective) She is [a teacher] (noun)
An entire clause can also function as the complement of a verb in a sentence. It is referred to as a clause complement but functions similarly as a noun complement. He knows [her] He know [the fact that she is unhappy]

5. Complementizer
A functional category that connects the main or pivotal clause to the subordinate or dependent clause; it can be used to link the main clause of the sentence with complement clause.
Clausal complementizer: Attaches an entire clause to a higher matrix sentence as its argument, with the embedded clause treated as a noun category She said that [Mary is a good girl]
Infinitival complementizer: Infinitival marker that attaches the infinite clause to the main or matrix clause, Sam wants to [eat apples]

6. Gerundival complementizer:. Attaches a gerund, i. e
Gerundival complementizer: Attaches a gerund, i.e., verbal participle, that behaves as a noun to the main clause I like [bathing in the sea].