In this paper, we will give a unified account of the cross-linguistic variation in the encoding of adjectives in predicative and attributive constructions. Languages may differ in the encoding strategy of adjectives in the predicative domain (Stassen 1997), and sometimes change this strategy in the attributive domain (Verkerk 2007). We will show that the interaction of two principles, that of faithfulness to the semantic class of a lexical root and that of faithfulness to discourse functions, can account for all attested variation in the encoding of adjectives.