The third part of the work, which contained twelve books, treated of syntax, or the junction of words, so as to form a phrase or sentence. It also contained a sort of glossary, which explained the true meaning of Latin vocables.
This, which may be considered as one of the chief works of Varro, was certainly a laborious and ingenious production; but the author is evidently too fond of deriving words from the ancient dialects of Italy, instead of recurring to the Greek, which, after the capture of Tarentum, became a great source of Latin terms. In general, the Romans, like the Greeks before them, have been very unfortunate in their etymologies, being but indifferent critics, and inadequately informed of everything that did not relate to their own country. Blackwell, in his _Court of Augustus_, while he admits that the sagacity of Varro is surprising in the use which he has made of the knowledge he possessed of the Sabine and Tuscan dialects, remarks, that his work, _De Lingua Latina_, is faulty in two particulars; the first, arising from the author having recourse to far-fetched allusions and metaphors in his own language, to illustrate his etymology of words, instead of going at once to the Greek. The second, proceeding from his ignorance of the eastern and northern languages, particularly the Aramean and Celtic(72); the former of which, in Blackwell's opinion, had given names to the greater number of the gods, and the latter, to matters occurring in war and rustic life.
It is not certain whether the _Libri De Similitudine Verborum_, and those _De Utilitate Sermonis_, cited by Priscian and Charisius as philological works of Varro, were parts of his great production, _De Lingua Latina_, or separate compositions. There was a distinct treatise, however, _De Sermone Latino_, addressed to Marcellus, of which a very few fragments are preserved by Aulus Gellius.
The _critical_ works of this universal scholar, were entitled, _De Proprietate Scriptorum_--_De Poetis_--_De Poematis_--_Theatrales__, sive de Actionibus Scenicis_--_De Scenicis Originibus_--_De Plautinis Comoediis_--_De Plautinis Quæstionibus_--_De Compositione Satirarum_--_Rhetoricorum Libri_. These works are praised or mentioned by Gellius, Nonius Marcellus, and Diomedes; but almost nothing is known of their contents.