Here's why:
* They add information: Prefixes provide additional meaning to the base word. They can indicate size, direction, negation, intensity, and more.
* They modify the base word: Prefixes essentially "modify" the base word, creating a new word with a different meaning.
* They create contrast: Some prefixes create opposites of the base word. For example, "un-" makes the word the opposite of its original meaning (happy vs. unhappy).
* They create nuances: Prefixes can subtly change the meaning of a word, even if they don't create complete opposites. For example, "pre-" implies something happening before something else (pre-game vs. game).
Examples:
* Happy vs. Unhappy: "Un-" negates the meaning of "happy"
* Large vs. Enormous: "En-" indicates a greater degree of size than "large"
* Run vs. Rerun: "Re-" indicates a repetition of the action "run"
* Write vs. Rewrite: "Re-" indicates a modification or improvement of the action "write"
* Possible vs. Impossible: "Im-" negates the possibility of the action "possible"
Understanding prefixes helps you decipher the meaning of unfamiliar words and expand your vocabulary.