The Diction viewed as a whole is made up of the following parts: the Letter (or ultimate element), the Syllable, the Conjunction, the Article, the Noun, the Verb, the Case, and the Speech. (1) The Letter is an indivisible sound of a particular kind, one that may become a factor in an intelligible sound. Indivisible sounds are uttered by the brutes also, but no one of these is a Letter in our sense of the term. These elementary sounds are either vowels, semivowels, or mutes. A vowel is a Letter having an audible sound without the addition of another Letter. A semivowel, one having an audible sound by the addition of another Letter; e.g. S and R. A mute, one having no sound at all by itself, but becoming audible by an addition, that of one of the Letters which have a sound of some sort of their own; e.g. D and G. The Letters differ in various ways: as produced by different conformations or in different regions of the mouth; as aspirated, not aspirated, or sometimes one and sometimes the other; as long, short, or of variable quantity; and further as having an acute grave, or intermediate accent.
The details of these matters we must leave to the metricians. (2) A Syllable is a nonsignificant composite sound, made up of a mute and a Letter having a sound (a vowel or semivowel); for GR, without an A, is just as much a Syllable as GRA, with an A. The various forms of the Syllable also belong to the theory of metre. (3) A Conjunction is (a) a non-significant sound which, when one significant sound is formable out of several, neither hinders nor aids the union, and which, if the Speech thus formed stands by itself (apart from other Speeches) must not be inserted at the beginning of it; e.g. men, de, toi, de. Or (b) a non-significant sound capable of combining two or more significant sounds into one; e.g. amphi, peri, etc. (4) An Article is a non-significant sound marking the beginning, end, or dividing-point of a Speech, its natural place being either at the extremities or in the middle. (5) A Noun or name is a composite significant sound not involving the idea of time, with parts which have no significance by themselves in it. It is to be remembered that in a compound we do not think of the parts as having a significance also by themselves; in the name ‘Theodorus’, for instance, the doron means nothing to us.
(6) A Verb is a composite significant sound involving the idea of time, with parts which (just as in the Noun) have no significance by themselves in it. Whereas the word ‘man’ or ‘white’ does not imply when, ‘walks’ and ‘has walked’ involve in addition to the idea of walking that of time present or time past.
(7) A Case of a Noun or Verb is when the word means ‘of or ‘to’ a thing, and so forth, or for one or many (e.g. ‘man’ and ‘men’); or it may consist merely in the mode of utterance, e.g. in question, command, etc. ‘Walked?’ and ‘Walk!’ are Cases of the verb ‘to walk’ of this last kind. (8) A Speech is a composite significant sound, some of the parts of which have a certain significance by themselves. It may be observed that a Speech is not always made up of Noun and Verb; it may be without a Verb, like the definition of man; but it will always have some part with a certain significance by itself. In the Speech ‘Cleon walks’, ‘Cleon’ is an instance of such a part. A Speech is said to be one in two ways, either as signifying one thing, or as a union of several Speeches made into one by conjunction. Thus the Iliad is one Speech by conjunction of several; and the definition of man is one through its signifying one thing.