When English some takes a singular NP, the resulting phrases reliably convey meanings not shared by variants with a(n) or plural NPs. Thus, whereas I met a friend and I met some friends are unmarked, I met some friend is associated with a range of affective meanings, especially speaker lack of interest in the referent. For semantic accounts, choosing some over its competitors is a choice to convey this uncertainty directly, which often leads to negative pragmatic inferences. We identify two challenges for semantic accounts of singular some. First, we present attested examples in which speakers use singular some to refer to entities that they themselves identify in the context. Second, we argue that semantic accounts miss an important generalization: some conveys these special meanings only if a is available as competitor. These challenges suggest a pragmatic source for the relevant meanings. We propose to derive them as manner implicatures, using similar logic to that of Weir (2012) but without encoding a fixed semantic contrast between a and some.To make this precise, we adopt the version of the Rational Speech Acts (RSA) model developed by Bergen et al. (2016), in which pragmatic reasoning leads synonymous forms that differ in marked-ness to take on different usage patterns. Attached is the full abstract.