This article reports on the results of a broad crosslinguistic study on the semantics of quantity words such as many in the superlative (e.g. most). While some languages use such a form to express both a relative reading (as in Gloria has visited the most continents) and a proportional reading (as in Gloria has visited most continents), the vast majority do not allow the latter, though all allow the former. It is argued that a degree-quantifier analysis of quantity words is best suited to explain why proportional readings typically do not arise for quantity superlatives. Based on morphosyntactic evidence, two alternative diachronic pathways through which proportional quantifiers may develop from quantity superlatives are identified.