Root words are the basic building blocks of language. They are the simplest form of a word, without any prefixes or suffixes added. For example, in the word unhappiness, the root word is happy. Understanding root words helps in deciphering the meanings of more complex words. By knowing root words, you can expand your vocabulary and improve your language skills. Many words in the English language share common root words, which can make it easier to learn new terms. For instance, the root word bio means life, appearing in words like biology and biography.