function word

The distinction between function/structure words and content/lexical words proposed by C.C. Fries in 1952 has been highly influential in the grammar used in second language acquisition and English Language Teaching. Function words are words that have little lexical meaning or have ambiguous meaning, but instead serve to express grammatical relationships with other words within a sentence, or specify the attitude or mood of the speaker. They signal the structural relationships that words have to one another and are the glue that holds sentences together. Thus, they serve as important elements to the structures of sentences.