It is important for students to understand that words can be broken down into morphemes, which are the smallest meaningful unit in a language. Words may consist of affixes (i.e., prefixes, suffixes). Affixes are additional elements that may be placed at the beginning or end of a root, stem, or word, or in the body of a word to modify its meaning.

Examples of prefixes:

• Anti- (against): antisocial, antifreeze

• Dis- (opposite of): dishonest, disagree

• In- (not): incomplete, inability

• Co- (with): cooperation, coworker

• Fore- (before): forehead, forecast

• Extra (More than): extracurricular, extraordinary

Examples of suffixes:

• -able- (can be done): preventable

• -ed- (past tense): laughed, played

• -ion- (the action or process of): celebration, interrogation

• -ment- (condition): movement, argument

• -s- (plural): girls, toys

• -er/-or (person): teacher, doctor

Students with learning disabilities sometimes have a hard time defining vocabulary words both orally and textually. In addition, students have difficulty defining words both in isolation and in context. In order to increase their understanding of Tier 2 and Tier 3 vocabulary words, it is important that educators explicitly teach affixes. Prefixes and suffixes have meaning, and therefore, adding them to a root word changes its definition.

To promote generalization, the teacher can assign students into groups of two or three. After assigning homogenous groups, the teacher can give out short paragraphs on the students’ instructional reading levels. The paragraphs will differ based on topic, content, and subject area. Students will be instructed to decode the text, highlight root words in yellow, and affixes in red. After locating the words in the text, students will write the words on a recording sheet and label the meaning of each word part. For example, if the word is “unforgettable,” the student would highlight “forget” in yellow, and “un-” and “-able” in red. Here, students would define “un-” as (not) and “-able” as (can be done). Given the clues presented in this word, unforgettable means not able to be forgotten. Students will use this skill to define unfamiliar words within the assigned paragraphs.