AFFIXES ATTATCH TO A ROOT TO FORM A NEW WORD.  THERE ARE TWO FORMS OF AFFIXES: PREFIXES AND SUFFIXES.  A PREFIX IS AT THE BEGINNINGS OF A ROOT WORD.  AND A SUFFIX IS AT THE END OF A ROOT WORD.
COMMON PREFIXES COMMON SUFFIXES
PREFIX MEANING EXAMPLE SUFFIX MEANING EXAMPLE
ANTI AGAINST ANTIGRAVITY ABLE  CAN BE DONE, ABLE TO DOABLE, TEACHABLE
DE OPPOSITE DEFROST EST COMPARATIVE BIGGEST
PRE BEFORE PREHISTORIC FUL FULL OF GRACEFUL, USEFUL, CAREFUL
RE AGAINST REDO LESS WITHOUT, MISSING, OF NO HAIRLESS, USELESS, CARELESS
UN NOT UNTIE LY LIKE, MANNER OF, CHARACTERISTIC OF, BEING SLOWLY
DIS OPPOSITE OF  DISAGREE MENT ACTION OR PROCESS ENJOYMENT
NON NONSENSE NONSENSE NESS STATE OF, STATE OF BEING  HAPPIENESS
MIS WRONGLY MISSPELL ITY STATE OF  INFINITY
TRANS ACROSS TRANSATLANTIC ER ONE WHO, PERSON OR THING THAT DOES SOMETHING WORKER, TEACHER
IN  NOT INACTIVE TION ACT  ACTION
EN TO CAUSE TO BECOME
OUS FULL OF
SUFFIX SPELLI NG RULES
WHEN ADDING A SUFFIX TO A BASE WORD, THE SPELLING OF THE BASE WORD MAY CHANGE.
EXAMPLE:  HAPPY + NESS = HAPPINESS
DOUBLE THE CONSTANT AT THE END OF MANY SHORT WORDS WHEN ADDING THE SUFFIX.  
EXAMPLE:  RUNNER, KIDDING