Which tier of vocabulary encompasses common, everyday words most children already know?

Tier 1 vocabulary consists of the basic words that are commonly used in everyday speech and are typically understood by most children without needing specific instruction. These words include concrete nouns, simple verbs, and basic adjectives that relate to familiar objects and experiences, such as "dog," "run," and "happy." Children learn these words early in their education and life experiences, which makes them integral to their ability to communicate effectively in everyday situations.

The other tiers represent different levels of vocabulary complexity. Tier 2 vocabulary includes more sophisticated words that are often found in written texts and may require explicit teaching, such as "analyze" or "sophisticated." Tier 3 vocabulary pertains to domain-specific terms that are usually found in specialized contexts, like "photosynthesis" in science, and thus are not commonly used in everyday conversation. Content vocabulary refers to the words that are essential to understand a specific subject area, further indicating that these terms have a narrower application than Tier 1 vocabulary. This differentiation helps educators focus on the appropriate level of vocabulary instruction based on students' needs.