An affix is a bound morpheme that is attached to a free morpheme or a root (word) to modify its meaning. E.g. the English word happy is a root. There are a few categories of affixes: prefix and suffix.
Prefix is an affix or a bound morpheme that is added to the beginning of a word or a morpheme. E.g. unhappy. On the other hand, suffix is a bound morpheme that is attached at the end of a root word. E.g. happiness.
A suffix is an affix that follows a word to modify its meaning. Eg. teacher, catches, dogs, etc in English equivalency. In ASL, the agent suffix is one example.
This person sign (left) becomes an agent suffix that is added to a sign to produce a profession, role, or identity of what does a person do. Eg. teacher, dancer, American, athlete, etc. However, it does not apply to some of the other terms, like doctor, adult, etc.
[L] This is the regular sign for 'teach' (also 'teaching', 'taught', etc). [R] This sign has the agent suffix added to it, which becomes teacher.
It is directly translated as 'sports' + 'person', meaning athlete.
It means author, directly translated as 'write' + 'person'.
This student sign has a suffix; however, it is not the same suffix sign as the previous ones. It was evolved originally from the signs, LEARN + AGENT (PERSON).
A suffix is an affix that follows a word to modify its meaning. Below shows an affix in ASL to denote comparative (-er) and superlative (-est). The affix in this case is the movement parameter.
These ASL words mean good, better, and best, respectively.