From Sagesse to Liturgies intimes, Verlaine pays more attention to dialects and especially northern French dialects (“langue d’oïl”). The interest the poet takes in them can be explained by the publication of the Recueil sur les patois in 1880, that collects letters and documents about Henri Grégoire’s investigation during the French Revolution (1790-1794). But it is also linked to the development of the contemporary dialectology, and above all the Revue des patois gallo-romains (1887). However, the literary endeavour of the writer appears quite different from those new scientific methods. Verlaine questions the historiography of the French language and its dualistic view between the idiomatic standards and the vernacular uses. According to him, lyric productions must receive a various set of linguistic forms. That’s why the poet is first attached to regional accents, beyond syntactic or lexical criteria in the northern French vernaculars. He applies to integrate the vernacular oral forms into his poetry, although they decline in the nineteenth century. But Verlaine’s stance includes a political purpose against the Jacobin ideology : the poetics of the dialects enhances the values of popular habits or local ways of life and finally of very threatened minorities cultures.