This study examines two examples of grammatical variation in Norwegian inflection, strong versus weak verb conjugation and affixal versus periphrastic adjective comparison. The main claim is that they are not as arbitrary as one may think, they rather indicate a division of labour. The strong verb inflection tends to be motivated not only by phonology, but also by semantics. The affixal and periphrastic adjective comparisons tend to be used with different sets of adjectives and for different semantic purposes. These observations support the Principle of Contrast, the idea that a difference in forms normally will relate to a difference in some kind of meaning.