Is it true that teachers can teach students every word they need to know since vocabulary is a constrained skill?

The statement that teachers can teach students every word they need to know is false. Vocabulary is indeed a constrained skill, meaning that the total number of words in a language is vast, and no single individual can learn or be taught every word used in various contexts and disciplines.

Students encounter new words throughout their lives, and vocabulary acquisition is an ongoing process influenced by their experiences, exposure to language, and the specific contexts in which they engage with words. While teachers play a critical role in helping students expand their vocabulary through direct instruction and rich language interactions, they cannot cover the entirety of a language's vocabulary. Instead, teaching strategies should focus on developing skills for independent word learning, such as using context clues, word parts (prefixes, suffixes, roots), and other strategies that empower students to understand and learn new vocabulary on their own. This approach cultivates a lifelong learning mindset regarding language, allowing students to adapt to new words and changing meanings as they grow.