In Singapore, government language policy promotes Mandarin as the official Chinese variety, while discouraging the use of other Chinese ‘dialects’. This article examines Singaporean citizens' comments in blogs and discussion forums about the value and relevance of these stigmatised languages. Although these online discourses overtly contrast with state discourses in their positive evaluations of the non-Mandarin languages, both bodies of discourse presuppose a common ground of language ideology: namely, that a language is an alienable commodity that can be actively manipulated and that it possesses a specific value. The discourses also follow shared patterns of constructing sociolinguistic difference through semiotic processes of iconisation, recursivity, and erasure. My analysis distinguishes between the discourses' implicit language-ideological presuppositions and their explicitly articulated linguistic-evaluative content and traces the interrelation of these. The shared presuppositions are important for actors' bids to enlist (different) normative sociolinguistic hierarchies in the service of projects of hegemonic nation-building, as well as for the purposes of politically subversive identity work.