This study deals with synchronic variation through a diachronic lens. Mismatches between syntactic and semantic properties are usually rooted in diachronic development. This study addresses this layer of synchronic-diachronic association through the analysis of how numeral phrases referring to a small quantity have developed as polarity sensitive items in Mandarin Chinese. The analysis will show how a polysemy network has developed by being associated with semantically and syntactically relevant constructions. In order to capture the tendencies of language change, a longitudinal corpus study is conducted to examine how constructions have developed internally and how that development has been conditioned by linguistic factors external to the constructions in question. The skewed distribution of numeral phrases as polarity items in different word order patterns is conditioned by multiple related factors, such as specificity, quantification, scalarity, negation, and focus. The study aims to incorporate these factors from a diachronic perspective with an account of how the synchronic variation of numeral phrases reflects a series of syntactic and semantic changes in the history of Chinese.