This work is about the Grammatica Philosophica da Lingua Portugueza (1822), by Jerônimo Soares Barbosa, a grammar based on general grammar theory. The purpose of the research was to demonstrate Barbosa's theoretical affiliation to the principles of rationalist theory by studying the verbal system organized by the grammarian. Based on the History of Linguistic Ideas, we examine and interpret from Chapter VI -The verb, from Book III -From Etymology, or parts of the portuguese phrase, the following sections: the concept of verb; Article I -Of the substantive verb, and its auxiliaries; Article II -The conjugation of the substantive verb and its auxiliaries; Article III -The adjective verb and § I -Conjugation of the adjective verb in his active voice of this same article. For the development of this analysis, the work was divided into four chapters: in the first one, according to Auroux (1979Auroux ( , 1922Auroux ( , 1998aAuroux ( , 1998bAuroux ( , 2008Auroux ( , 2009a, we identified and examined Barbosa's retrospection horizon; in the second one, according to the concepts of grammar presented in the Port-Royal General Grammar (GGP-R) and in the Encyclopedie articles Grammaire (1757) and Mot (1751) , we analyze the definition of grammar proposed in the Grammatica Philosophica da Lingua Portugueza (GPLP); In the third part, we initially perform a historical reflection on logos in search of the relevance of the verb in the composition of the proposition, and then describe and analyze the terminology and concept of the verb in GGP-R, Grammaire Générale (BEAUZÉE, 1767), Grammaire (CONDILLAC, 1775), Grammatica Philosophica (BACELLAR, 1783), Gramatica Portugueza (SOUZA, 1804), and GPLP (1822), for a comparative and interpretative study of these grammars; and, in the fourth chapter, we look at the mode and tense conceptions of the verb in the general and philosophical grammars discussed earlier, and then reflect on the criteria used in the GPLP for the conception of mode and tense in order to identify and discuss the causes of reorganization of the verbal system in this work. Through description and analysis, we find that the verbal system in GPLP results from the application of the concepts presented in the general and philosophical grammars preceding the work, of which Barbosa partially appropriated, since: a) the verb to be remains as an essential component of the proposition; b) the essence of the verb is the meaning of "existence"; however, c) the auxiliary verb receives a new interpretation; and d) the system of verb tenses and verb modes is organized on the basis of the functional-syntactic criterion whereby tenses are distributed only into three verb modes. Research shows that while Barbosa is grounded in the principles of general grammar, the verbal system set forth in the GPLP is not just a simple copy, but there is a critical interpretation of the systems presented in the Port-Royal, Beauzée, and Condillac grammars to externalize an different proposal to the verbal system of the Portuguese language.