How does a prefix modify a word?

A prefix modifies a word by being added to the beginning of it. This attachment directly changes the word's meaning, making it more specific than the original root word. For instance, adding the prefix "un-" to the word "happy" changes its meaning to "not happy." The modification occurs because the prefix carries its own meaning, which alters the overall significance of the root word once combined. Thus, prefixes are essential tools in language that help expand vocabulary and convey different nuances.