Learn how to double your English vocabulary instantly, with prefixes

Legendary movie star Audrey Hepburn once said “Nothing is impossible -- the word itself says I’m possible!” 

This is a lovely sentiment, and a cute pun, but it’s not true in English grammar. When we speak English, we can often change positive words to their negative meaning (and vice versa) by adding a prefix (in this case “im”). In this article we will look at the most common prefixes in English, and how and when to use them.  

A prefix is a group of letters that's added to the beginning of a word. Prefixes in English modify the meaning of that word. They can make the word negative, show repetition, or indicate an opinion.  
 
Prefixes are common in English. When you learn how to use them, you instantly double your vocabulary -- simply by adding prefixes to English nouns and adjectives you already know. 
 
Having said this, the fastest way to expand your English vocabulary is to take English classes with expert teachers. Find classes here

When do we use prefixes in English?  

We usually use prefixes before adjectives to give them the opposite meaning. For example, kind becomes unkind. When we use a prefix before a verb or nouns, prefixes give us more information about the word or situation -- for example, eat can become overeat, and understanding can become misunderstanding.  

Here are some of the most common prefixes for adjectives which we use for negation, or for saying “not”.  
 
Note that using a prefix like this does not always make the word negative – it just makes it not the same. For example, when you add the prefix in- to dependent you make the word independent.  And that’s not bad!  

How do you know when you use each English prefix? 

So should you use im- or un- or another prefix? How do you know what word goes with each prefix? Good question. It is mostly to do what sound is easiest to pronounce. 
 
Here are common sets of prefixes -- although there are exceptions:  

Im- is often used in front of adjectives that begin with p, m, b 
(immature, imbalanced) 

In- is often used in front of other adjectives.   
(Incompetent, ineffective) 

Ir-  is often used before adjectives that begin with r.  
(irrelevant, irresponsible) 

il-  is often used before adjectives that begin with l.  
(illegible, illicit)  

We can also use prefixes to add other meanings to words:  

Learn the easy spelling rules for English prefixes 

The rules for spelling English prefixes are simple. The spelling of the root word does not change, neither does the spelling of the prefix. This often means using double letters: 

My little brother is so immature. 
I couldn’t read the document -- it was illegible. 
Bob thought the meeting was unnecessary.  

Some prefixes use a hyphen (-) before the main word. For example with the prefix ex- . You should also use a hyphen if a prefix comes before a proper noun, name or number: 

I saw my ex-boss at the conference. He was looking very stressed! 
They were very pro-Europe, even though their friends were anti-Europe. 
I used to listen to this music in the mid-90s. 

You also need hyphens when the prefix ends with the same vowel the main word begins with. This helps make the word easier to pronounce.  

Everyone was hoping that they wouldn’t re-elect the Treasurer. 
She is one of the world’s pre-eminent physicists. 

With other prefixes, you should only use a hyphen if the meaning isn’t clear without one. Look at this example of very different meanings:  

Ahmad had to re-sign the document.  (He had to sign the document again.) 
Ahmad had to resign from his job, as he had found something better.  (He had to leave his job). 

Common mistakes using English prefixes  

Often people make mistakes using different prefixes that seem similar, but the meanings are not exactly the same. For example: 

He was very dissatisfied with his new headphones -- the sound quality was terrible. 

John was unsatisfied after the meal -- he was still hungry. 

The words are similar, and they’re both negative. But the meaning is slightly different. Dissatisfied means someone is unhappy or frustrated with something. But unsatisfied means something is not complete, or something is missing.  

Famous examples of prefixes in popular movies and music 

The 2008 song by French duo Air called “Lucky and Unhappy ” is about nonconformists voting for a freestyle life.