Adding a prefix or a suffix to a word

1 - Prefixes & suffixes

Prefixes and suffixes are letters combinations such as dis in disagree 
and ing in shopping that can be added to a word to change its meaning 
or its grammatical function. Prefixes are added to the beginning, suffixes 
 to the end of the word.
A prefix changes the meaning of a word. A suffix changes the grammatical 
function of the word.
The word to which the prefix or suffix is added is called the base or root. 
Example:
-------

 Un 
separ
 able 
Prefix
 base 
suffix


   
When a word is added to a base word, the spelling of both the prefix and 
the base remains absolutely unchanged even if the last letter of the prefix is 
the same as the first letter of the base. But when certain suffixes are added 
to certain base words, however, the spelling of the base word may change 
in one of three ways:

The letter y may change to i: 
busy + -ness →  business
lazy + -ly → lazily 
 The letter e may be dropped:
type + -ist →  typist
hope + -ing →  hoping
The last letter of the base word may be doubled:
run + -er →  runner
hop + -ing →  hopping              

 


2 - How to change: Y to I? :

When a suffix is added to certain words ending in the letter y, 
The y changes to an i if the letter before the y a consonant.
Exceptions:
- If the suffix already begins with an i  (ing)
- Shyness, dryness, slyness
- The y does not change to an i f the letter before the final y is a vowel, 
Exceptions: daily

 
3- How to drop the final letter “e”? :

The letter e is silent at the end of the word. It often changes the pronunciation 
of a vowel that comes earlier in the word. Notice the difference in the way you 
pronounce sit and site.

Final e is usually dropped before a suffix that begins whit a vowel:
Examples:
--------
move + -ing →  moving
move + -er →  mover
move + -able →  movable

But: final e is not dropped before a suffix that begins whit a consonant:
move + -ment →  movement 
(The suffix begins with a consonant. So the e is kept.)
Exceptions: truly, argument

When a c or a g comes before the final e, as in notice and courage, the final 
e is dropped only before suffixes beginning with the vowels: e or i.
Examples:
--------
manage + -er →  manager       
manage + -ing →  managing
But:
manage + -able →  manageable
 
4- How to double the final consonant: 

4-1 One syllable words:
A lot of English words end in combination: consonant-vowel-consonant 
(CVC),
Examples:   Shop, set, run, …
One-syllable words with the CVC ending
double the final consonant before a suffix that begins with a vowel. 
Examples:
--------
shop + -ing →  shopping
hid + -en →  hidden
But: for suffix that begin with a consonant, no Doubling.
Examples:
--------
glad + -ly →  gladly
glad + -ness →  gladness                     
Exception: 
The letter x (combination of two consonants) sounds k and s. 
We don’t double it. 
Fix + -ing  →  Fixing.

Notice that we can double the final consonant only when the word ends 
with CVC. Some words ends with a consonant, but not with CVC. 
Furthermore, the final consonant would not be doubled before any suffix:
Examples:
--------
learn + -ing →  learning
speak + -ing →  speaking


4-2 - words of more than one syllable:
It depends on where the syllable is stressed in the word with the 
suffix added.
If the stress is on the last syllable of the base word, the final 
consonant is doubled, the word must end whit CVC and the suffix 
must begin with a vowel.   (Exception: words ending with x or w)
Examples:
--------
 Double consonant:
prefer + -ing →  preferring      
prefer + -ed →  preferred 

Do not double consonant:
prefer + -ence →  preference 

Others examples:
The accent (stress) is on the last syllable for:
admit - prefer - equip - forgot  - begin - propel -...
(the last letter can be doubled)

The accent is on the first syllable for: 
transmit - garden - refer - forbid - number - permit
 - profit - unforget - perform - enter - regret - invent - 
compel - contend - suffer - defer - pilot -...
(the last letter cannot be doubled)

 

5- Summary:  Prefixes and suffixes

A prefix usually changes the meaning of a word.
A suffix usually changes the grammatical function of a word.
5.1- Words ending in the letter Y:
- The letter before Y is a vowel: No change.
Exception:  daily.
- The letter before Y is a consonant: Change Y to an I.
Exceptions:
- Whether the suffix already begin with an I (ING).
- And: shyness, dryness, and slyness. 
5.2-Dropping the final letter e:
Final e is dropped before a suffix that begins with a vowel. Do not
drop this final e before a suffix that begins with a consonant,
Exception: truly and argument.

When C or G comes before the final e. This letter 
e is dropped only if the suffix begins with I or E (not with a or any consonant)
Exception: judgment, acknowledgment.

5.3-Doubling the final consonant: 
5.3-1- one-syllable words.
CVC – double with vowel.
No double with consonant.
For Fix [→ Fiks]: no double).
5.3-2 Words of more than one-syllable.
Here’s the rule:
Words with CVC and the suffix as a vowel.
Pronounce the word with the suffix added. If the stress
falls on the last syllable of the base word, the final
consonant is doubled.