This review article deals with the monographical study of Bernez Rouz (Bernard Le Roux): Alain Dumoulin. Un recteur breton dans la tourmente révolutionnaire (Ed.
Arkae, 2011). It proposes an analysis of Dumoulin''s Grammatica latino-celtica, the Breton grammar created and published in Prague (1800), examinating its philological as well as historical importance.