On word classes

In this article we discuss some basic questions relative to word classification, namely: the type of unit that should be classified (words, not lexemes); the need to set up clear objectives to classification; and the rigorous distinction between classes (based on paradigmatic relations) and functions (based on syntagmatic relations). We then consider the traditionally accepted distinction between "adjectives" and "nouns", and we show that this is not a class distinction, but rather a functional distinction. Thus, adjectives and nouns are not distinct word classes in Portuguese.