Two matters, then, are of vital importance in language,—the forms of words, and the relations of words. The science which treats of these two matters is called grammar.

Inflection is a change in the form of a word indicating some change in its meaning.

The relation in which a word stands to other words in the sentence is called its construction.

Grammar is the science which treats of the forms and the constructions of words.

Syntax is that department of grammar which treats of the constructions of words.

Grammar, then, may be said to concern itself with two main subjects,—inflection and syntax.

English belongs to a family of languages—the Indo-European Family[1]—which is rich in forms of inflection. This richness may be seen in other members of the family,—such as Greek or Latin. The Latin word homo, “man,” for example, has eight different inflectional forms,—homo, “a man”; hominis, “of a man”; homini, “to a man,” and so on. Thus, in Latin, the grammatical construction of a word is, in general, shown by that particular inflectional ending (or termination) which it has in any particular sentence. In the Anglo-Saxon period,[2] English was likewise well furnished with such inflectional endings, though not so abundantly as Latin. Many of these, however, had disappeared by Chaucer’s time (1340–1400), and still others have since been lost, so that modern English is one of the least inflected of languages. Such losses are not to be lamented. By due attention to the order of words, and by using of, to, for, from, in, and the like, we can express all the relations denoted by the ancient inflections. The gain in simplicity is enormous.

II. Grammar and Usage

Since language is the expression of thought, the rules of grammar agree, in the main, with the laws of thought. In other words, grammar is usually logical,—that is, its rules accord, in general, with the principles of logic, which is the science of exact reasoning.

The rules of grammar, however, do not derive their authority from logic, but from good usage,—that is, from the customs or habits followed by educated speakers and writers. These customs, of course, differ among different nations, and every language has therefore its own stock of peculiar constructions or turns of expression. Such peculiarities are called idioms.