What is the difference between content & function words?
Function words are the shortest and most common words that we use. They include pronouns, articles, prepositions, conjunctions, negations, auxiliary verbs, and a small group of common adverbs. Although there are only about 500 function words, they account for over 60% of all the words you say, hear, or read.
They are also unconscious words, people do not think about these words when using them, and therefore they provide deeper insight into the unconscious of what is being said.