Plutarch's Platonic questions (10.1)

WHY SAID PLATO, THAT SPEECH WAS COMPOSED OF NOUNS AND VERBS?[*]

For he seems to make no other parts of speech but them. But Homer in a sportive humor has comprehended them all in one verse:

Αὐτός ἰὼν κλισίηνδε τὸ σὸν γέρας, ὄφρ εὖ εἰδῇς.

[*]

For in it there is pronoun, participle, noun, preposition, article, conjunction, adverb, and verb, the particle -δε being put instead of the preposition εἰς; for κλισίηνδε, to the tent, is said in the same sense as Ἀθηνάζε to Athens. What then shall we say for Plato?

Is it that at first the ancients called that λόγος, or speech, which once was called protasis and now is called axiom or proposition,—which as soon as a man speaks, he speaks either true or false? This consists of a noun and verb, which logicians call the subject and predicate. For when we hear this said, Socrates philosophizeth or Socrates is changed, requiring nothing more, we say the one is true, the other false. For very likely in the beginning men wanted speech and articulate voice, to enable them to express clearly at once the passions and the patients, the actions and the agents. Now, since actions and affections are sufficiently expressed by verbs, and they that act and are affected by nouns, as he says, these seem to signify. And one may say, the rest signify not. For instance, the groans and shrieks of stage-players, and even their smiles and reticence, make their discourse more emphatic. But they have no necessary power to signify any thing, as a noun and verb have, but only an ascititious power to vary speech; just as they vary letters who mark spirits and quantities upon letters, these being the accidents and differences of letters. This the ancients have made manifest, whom sixteen letters sufficed to speak and write any thing.