Use word-formation, prefixes, suffixes and common roots to understand new words and choose the correct word form

What this dot point is asking

This dot point is about using the building blocks of English words to do two jobs: work out what an unfamiliar word means, and choose the correct form of a word for a sentence. Most longer English words are made from a root carrying the core meaning, plus a prefix that adjusts the meaning and a suffix that fixes the part of speech. If you can spot those parts, an unknown word becomes far less frightening, and the editing and writing tasks become more accurate. The skill is examined directly in word-form questions and quietly rewarded everywhere your vocabulary shows.

The answer

Roots carry the core meaning

A root is the part of the word that holds its central idea. Many English roots come from Latin and Greek and recur across dozens of words. Knowing a handful unlocks a whole family. For example, the root "port" (to carry) appears in "transport", "export", "import" and "portable"; the root "spect" (to look) appears in "inspect", "spectator", "spectacle" and "respect". When you meet a new word, ask whether a familiar root sits inside it. "Audible" contains "aud" (to hear), so it must have something to do with hearing, and indeed it means able to be heard.

Prefixes change the meaning

A prefix is added to the front of a root and adjusts its meaning, very often by reversing or intensifying it:

• Negative or reversing: "un-", "in-", "im-", "dis-", "mis-", "non-". "Unhappy" is not happy; "disagree" is to not agree; "misjudge" is to judge wrongly.
• Position or direction: "pre-" (before), "post-" (after), "sub-" (under), "trans-" (across). "Preview" is to view before; "submarine" is under the sea.
• Number or degree: "re-" (again), "over-" (too much), "uni-" (one), "bi-" (two). "Rewrite" is to write again; "overcrowded" is too crowded.

Spotting the prefix often gives you half the meaning of an unfamiliar word at once.

Suffixes fix the part of speech

A suffix is added to the end and usually decides whether the word is a noun, verb, adjective or adverb. This is the part most tested in word-form questions:

• Noun suffixes: "-tion", "-ment", "-ness", "-ity", "-ence". "Decide" becomes "decision"; "happy" becomes "happiness".
• Adjective suffixes: "-ful", "-less", "-ous", "-ive", "-able". "Care" becomes "careful" or "careless"; "create" becomes "creative".
• Verb suffixes: "-ise", "-ify", "-en". "Modern" becomes "modernise"; "strength" becomes "strengthen".
• Adverb suffix: "-ly". "Quick" becomes "quickly".

To pick the right form, decide what the sentence slot needs (a thing, an action, a description, or how something is done) and reach for the matching suffix.

Examples in context

Example 1. One root, a whole family. A student who learns that "vis" and "vid" mean "see" can unlock "visible" (able to be seen), "invisible" (not able to be seen), "vision" (the act of seeing), "visualise" (to see in the mind) and "evidence" (what can be seen and shown). Meeting the unfamiliar word "envision" in a passage, the student spots the root "vis", reads the prefix "en-" (to make or bring into), and reasonably works out that it means to picture or imagine something in the future. The root turned an unknown word into a sensible guess.

Example 2. The same root, different forms for different slots. Take the root "create". A writing task might need the verb ("Engineers create new designs"), the noun ("the creation of new designs"), the adjective ("a creative design") or the adverb ("designed creatively"). A candidate who controls the suffixes can supply whichever form the sentence demands, while one who only knows "create" is stuck when the slot calls for "creativity" or "creatively". Choosing the right form for the slot, not just the right word family, is exactly what the word-form task rewards.

Try this

• Cue. Form the correct word from "STRONG" in: "The bridge was built to add ___ to the old structure." The slot after "add" and before "to" needs an abstract noun, so use the suffix that turns the adjective "strong" into a noun, giving "strength".

• Cue. The unfamiliar word is "irreplaceable". Break it into "ir-" (a form of "in-", meaning not), "replace" (to put something new in place of), and "-able" (able to be), and combine the parts to reach the meaning: not able to be replaced.

• Cue. Form the correct word from "ACT" in: "She responded ___ to the emergency." The blank describes how she "responded", so an adverb is needed; turn "act" into the adjective "active", then add "-ly" to give the adverb "actively".