Along with French, the official language of the Flemish Region is the Belgian variety of standardized Dutch.

An excerpt from the article 44 facts about Ghent

The people of Ghent speak the Ghent dialect, which has been heavily influenced by French (at the end of the 19th century, French was spoken in Ghent by 20% of the population). To date, the Ghentian language contains a great many French words, and they also pronounce the "r" voice peculiarly.