But these two classes, in the processes of formation, are not held sharply apart. There is hardly a suffix by which action-nouns are formed which does not also make agent-nouns or adjectives; although there are not a few by which are made only the latter. In treating them in detail below, we will first take up the suffixes by which derivatives of both classes are made, and then those forming only agent-nouns.

a. To facilitate the finding of the different suffixes is given the following list of them, in their order as treated, with references to paragraphs: