Allen & Greenough · Part First — Words and Forms › Formation of Words

§232. Derived Stems and Suffixes

Derived Stems are formed from roots or from other stems by means of suffixes. These are:—

Primary: added to the root, or (in later times by analogy) to verbstems.
Secondary: added to a noun-stem or an adjective-stem.
Both primary and secondary suffixes are for the most part pronominal roots (§ 228. 2), but a few are of doubtful origin.
Note 1.—The distinction between primary and secondary suffixes, not being original (see § 227), is continually lost sight of in the development of a language. Suffixes once primary are used as secondary, and those once secondary are used as primary. Thus in hosticus (hosti + cus) the suffix -cus, originally ko- (see § 234. 2.12) primary, as in paucus, has become secondary, and is thus regularly used to form derivatives; but in pudīcus, aprīcus, it is treated as primary again, because these words were really or apparently connected with verbs. So in English -able was borrowed as a primary suffix (tolerable, eatable), but also makes forms like clubbable, salable; -some is properly a secondary suffix, as in toilsome, lonesome, but makes also such words as meddlesome, venturesome.
Note 2.—It is the stem of the word, not the nominative, that is formed by the derivative suffix. For convenience, however, the nominative will usually be given.

J. H. Allen and J. B. Greenough, New Latin Grammar (Boston: Ginn, 1903). Text provided under a CC BY-SA license by Perseus Digital Library, http://www.perseus.tufts.edu, with funding from the National Endowment for the Humanities.