It was legal to park on that street at night.

If you add the prefix il- (meaning “not”) to the beginning of the word, you get the word illegal. See how the meaning of the sentence changes. In the dictionary, you will find prefixes listed alphabetically, looking like this: il-

It was illegal to park in that lot at night.

In addition, you can add the suffix “ly” (changing the word from an adjective to an adverb) to the end of the word. Now the sentence must change its structure to accommodate an adverb rather that an adjective. You will find suffixes listed alphabetically in the dictionary, looking like this –ment. Look at these sentences.

It was parked legally in that lot all night.

It was parked illegally in that lot all night.

Look at the chart below to see more examples of how new words can be made by adding prefixes and/or suffixes. Notice that sometimes, there is a small change in spelling in the root word before the affixes can be added.

Study this chart to become familiar with some prefixes, root words, and suffixes.