You’re 'in-' for some confusion with prefixes

Mar 16, 2014

If something is inflammable, it is no longer entirely clear whether we can set it on fire, or we can’t.

On this week’s edition of That’s What They Say, host Rina Miller and University of Michigan English Professor Anne Curzan take on the prefix “in-.”

There are two types of “in-” prefixes, and although they sound the same, they have different meanings. The first “in-” means “in or into,” like the examples income and inland. The second “in-” means “not,” as in the words inedible or incomprehensible.

The term inflammable uses the “in or into” meaning of the prefix. Consequently, something that is inflammable can be put into flame.

However, the prefix has caused some confusion.

“Well, some people think it means the opposite,” Curzan explains. “When they hear inflammable, they think that the ‘in-’ is the ‘not’ meaning, which means this is not flammable.”

To avoid this dangerous misunderstanding, many companies decided to use the term flammable rather than inflammable.

Invaluable is another confusing word with the “in-” prefix.

“The ‘in-’ does mean ‘not,’ but it’s not that the thing isn’t valuable,” Curzan describes. “The thing is so valuable, that it cannot be valued.”

In other cases, the “in-” prefix takes on new spellings. Before the letter “l,” “in-” becomes “il-.” Before an “r,” “in-” transforms into “ir-.” Finally, before bilabial sounds, “in-” changes to “im-.” These rules explain the terms illegal, irregular and impossible. 

Are you intimidated by the “in-” prefix? Let us know by commenting on our Facebook page or on our website.

-Clare Toeniskoetter, Michigan Radio Newsroom