Word formation: affixation

non-(non+performer=nonperformer; non+inclusion)
pre- (pre+modify=premodify; pre+occupy=preoccupy)
Suffixes are added after a word. Examples of suffixes include:
-s   (boy+s=boys; read+s=reads)
-es (go+es=goes; box+es=boxes)
-ies (lady+ies=ladies; study+ies=studies)
-ing (go+ing=going; read+ing=reading)
-ed (jump+ed=jumped; form+ed=formed)
-er (big+er=bigger; tall+er= taller) 
-est (big+est=biggest; tall+est=tallest)
There are other types, which are the main focus in this lesson. When these types of suffixes are added to a word, for example, a verb, they can change the verb to a noun, and change the noun to an adjective, and change the adjective to an adverb. Examples include: 
-er ---- teach (verb) + er = teacher (noun); pray (verb) + er = prayer (noun)