What are root words primarily used for in language?

Root words play a crucial role in the formation of complex words, as they provide the foundational meaning from which additional meaning can be derived. By adding prefixes, suffixes, and other morphemes to a root word, various related words can be formed. For example, the root word "act" can lead to "action," "react," and "activate," each of which carries a distinct meaning yet is connected to the same base idea. This process demonstrates how root words serve as building blocks for expanding vocabulary and enhancing language skills.

The other options do not accurately reflect the primary function of root words. While some root words can exist as standalone words, their primary significance in language is to aid in the creation of complex words that enrich communication. Root words do not hinder vocabulary development; rather, they support it by allowing learners to understand and connect various word forms. Additionally, root words do not establish grammar rules, which are separate and pertain to sentence structure and usage rather than the formation of individual words.