For a couple of decades now, in Flanders, the functional elaboration of what is generally called tussentaal, i.e. mesolectal language use situated in between (‘tussen’) acrolectal Standard Dutch and basilectal Flemish dialects, has caused increasing concern about the position of Standard Dutch relative to other recognized ways of speaking. This has provoked intense debate about the proper characterization of this evolution. This paper focuses on the daily language practices and overt attitudes of six girls at a Flemish secondary school to illustrate that it is relatively easy to find evidence that suggests this evolution is properly characterized as a type of destandardization. Yet by zooming in on the covert SLI-influenced language attitudes of the girls, I will argue that a close ethnographic study of daily language use is able to go beyond the surface appearances of larger-scale ideologies and can demonstrate the continuing influence of standardization. Sociolinguistic ethnography may therefore have a vital role to play in the ongoing debate about language variation in Flanders.