Language ideological debates are a constant feature of virtually all language contact situations, particularly in contexts of a conflictive nature. In this article, we analyse one recent debate about languages in Catalonia. In April 2016 a group of linguists and language professionals published a manifesto – the Manifest Koiné – that provoked an explosion of opinions in mass-media outlets in the region. In the article, we analyse both the content of the manifesto and the reactions that it sparked. Our analysis shows that in presenting the situation of Catalan in a rather pessimistic light, the manifesto finds itself in line with a long-solidified line of thought in the Catalan language imaginary. At the same time, the negative terms that are used to portray both Spanish and bilingualism in the manifesto are the points that gathered the strongest opposition during the debate. In addition, the single official status for Catalan in an imagined future independent state (the position implicitly endorsed by the manifesto) also was not supported in the debate. We conclude that these results are in line with the changing nature of the language ideological landscape that Catalonia has experienced over the last decades.