In their book (Casterman, 2004 ), Daniel Justens and Alain Préaux have documented how the Syldavian language is based on "Marols" or "Marollien", the dialect of the Marollen, a formerly working-class (though now trendy) quarter of Brussels. Marols, which Hergé learnt from his grandmother, is a form of Dutch incorporating many words of French origin as well as a sprinkling of Spanish. Syldavian seems to incorporate features of various Central European languages into the Marols foundation to suit Hergé's taste, such as German, Polish, Czech, and Hungarian. It is written both in Cyrillic and in Latin script, like Serbian.