What key concept is emphasized in the derivational relations stage of spelling development?

The key concept emphasized in the derivational relations stage of spelling development is the ability to derive many words from a single base word. This stage typically occurs in middle-grade students and focuses on how different prefixes and suffixes can be added to a root word to create new words with related meanings. For example, from the base word "act," one can derive "action," "react," "active," and "activity."

Understanding this relationship among words is crucial because it helps students build their vocabulary and develop a deeper understanding of language structure. This stage also encourages students to explore the meanings of words and their relationships to one another, enhancing both their spelling and literacy skills. In contrast to the other options, which focus on different aspects of spelling development, the derivational relations stage highlights the morphological understanding of language, making the ability to derive words from a base central to this stage.