The period of Humanism is a stage in the intellectual history of Europe during which language was understood not only as a means of communication, but also as a fundamental instrument shaping thought. In this era, the boundaries of cognition were redefined, and the philosophical analysis of the language–meaning relationship became a central focus. In this context, although Lorenzo Valla is usually known only for his work “The Donation of Constantine”, evaluating his philosophical views solely on the basis of this text does not sufficiently reflect the essence of the humanist language conception. The work in question, in addition to proving the falsity of a political document, also serves as a typical example of humanist linguistic thinking. The article analyzes Lorenzo Valla’s humanist language conception in comparison with the ideas of representatives of other humanist and philosophical traditions — Juan Luis Vives, Pietro Bembo, and William Ockham. In the research, Valla’s approach to the relationship between meaning and expression is examined through an analytical method, and his philological style is evaluated in terms of its influence on the formation of humanist thought. Furthermore, the study draws attention to the incorrectness of reducing Valla’s philosophical–linguistic views in academic literature to only one work, and investigates the process of development of the language conception in the period of Humanism through the historical-philosophical method. As a result, it is determined that Lorenzo Valla made a significant contribution to the development of both the philological and philosophical traditions in the history of humanist thought, and was one of the main humanists who reconceptualized the function of language in the cognitive process.