The purpose of this study is to shed light on whether and to what extent a community’s ‘official language ideology’ – its explicitly professed language policy – has an impact on the speech community as such. Does the official language policy influence community members’ values and valuations in the domain of language? Does the official language policy influence the ways that language is used in the community? If so, does its influence on use seem to happen in virtue of a great influence on values, or in spite of little influence on values? I shall attempt to answer these questions by making empirically based comparisons of ideology and use in two different settings. Our first setting will be the Danish speech community and its treatment of ideology and use in the ‘dialect vs. standard’ dimension; we may call this a study of ‘internal purism’. Our second setting will allow us to compare ‘external purism’ towards English across several Nordic speech communities. Thus, in both settings we will depart from a characterisation of ‘official’ language ideology, which in turn will be compared, firstly, to ‘lay’ language ideology – as this is offered both consciously and subconsciously (since this distinction has turned out to be of decisive importance) – and, secondly, to the facts of language use.