Valla's major contribution to Latin linguistics, and a widely spread humanist schoolbook.
"This work subjected the forms of Latin grammar and the rules of Latin style and rhetoric to a critical examination, and placed the practice of composition upon a foundation of analysis and inductive reasoning.
It was a basis for the movement of the Humanists to reform Latin prose style to a more classical and Ciceronian direction on a scientific basis.
Valla's work was controversial when it appeared, but its arguments carried the day.
As a result, humanistic Latin sought to purge itself of post-Classical words and features, and became stylistically very different from the Christian Latin of the European Middle Ages. This was thought to be a major improvement in style and elegance in Latin usage." (Wikipedia).