Functional systematization of the evaluative suffixes in the Brazilian Portuguese language investigates the morphemes traditionally known as augmentative and diminutive, having in mind specially its process of teaching-learning process in the Portuguese field as a second language for foreigners (PL2E). Though there are several forms of suffixes of this type, this paper opted to approach only the most productive ones: -(z)ão, -(z)aço and - (z)inho, and its respective feminine forms, - (z)ona, -(z)aça and -(z)inha, once its interest is in present-day Portuguese in use. The principal objective of this paper is to draw a functional formalization of such morphemes, taking as theoricmethodological base the Functional Discourse Grammar, recently devised by Hengeveld (2004a and 2004b) from the Theory of Functional Grammar, by Dik (1997b). The author intends to contribute to a bigger efficiency of the teachinglearning process of PL2E, as well as to a reflection about Portuguese as mother language that takes into account the foreigner perspective and allows it, therefore, to find strange and to understand it in all its aspects. The data analysis demonstrates that the use of these suffixes exceeds both the morphologic and semantic level, once it incurs in the pragmatic reality. Besides, the same analysis indicates that the evaluative suffixes rather translate the idea of increase or reduction than that of evaluation, which calls into question the widely used nomenclature, augmentative and diminutive, and ratifies the proposal of Rocha (1998), which generalizes them as evaluative suffixes.