H.I. Marrou, A History of Education in Antiquity
, tr. George Lamb (1956; rpt. Madison: University of Wisconsin Press, 1982), pp. 230-231:
Indeed the whole Latin language seems like the language of peasants (4). So many of the words that later developed a wider meaning began by being technical agricultural terms: laetus was first used to describe well-manured ground, felix, the fertility of the soil, sincerus, honey without beeswax, frugi, the profits, egregius, a beast separated from the rest of the herd—yet these came to mean "joy", "happiness", "truthfulness," "virtue" and "fame". Putare meant "to prune," then "to mark a stick with notches", then "to calculate", before it finally came to mean "to think".
Note 4 on p. 418:
"Le Latin, langue de Paysans": see the very illuminating essay under this title by J. MAROUZEAU in Mélanges linguistiques offerts à M.J. Vendryes, Collection Linguistique publiée par la Societé linguistique de Paris, 17, Paris, 1925, pp. 251-264, which refers to the classic work by A. ERNOUT, "Les Eléments dialectaux du Vocabulaire latin", in the same collection, 3, Paris, 1909, and the valuable pages in A. MEILLET, "Esquisse d'une Histoire de la Langue latine"4, pp. 94-118, and the chronological details in G. DEVOTO, Storia della lingua di Roma (Storia di Roma), Rome, XXIII, 1940, pp. 101-103.