Mandarin Chinese wh-pronouns are often analyzed as Negative Polarity Items (NPIs). The present study shows that Chinese wh-pronouns are not uniformly interpreted as NPIs. We focus on the interpretation of the wh-pronoun ji-ge 'how many-Classifier', which gives rise to a different interpretation in simple negative statements, which we call the 'small-amount' reading. To explain the availability of the 'small-amount' reading, we propose that ji-ge functions as both a singular existential quantifier and as a plural existential quantifier. When ji-ge is singular, it receives what we call a 'proform-N' reading. When ji-ge is plural, it either receives an 'at least two' reading or an 'a few' reading, depending on the linguistic context. On the proposed analysis, ji-ge is assigned the 'at least two' reading in simple negative statements, and the 'small-amount' reading is derived through a conversational implicature. To investigate the acquisition of these various readings of the wh-pronoun ji-ge, we conducted a comprehension study using simple negative statements. We found that children proceed through three developmental stages, each stage corresponding to different meanings of ji-ge. In two of the three stages, children assign non-adult interpretations, suggesting that children's analyses are not entirely determined by the linguistic input. This study sheds new light on the semantics of wh-pronouns in Mandarin Chinese.