But in fact it was fine. It helped that neither interlocutor was French or Belgian, so perhaps more merciful to non-native speakers, and that my programme assistant, whose native language is Spanish, has much better French than I do and was present in case of communications breakdown. The only tricky moment was in last week's meeting, where we were talking to a diplomat from a non-European Francophone country, who has only recently arrived in Brussels; I completely threw him when I said "nonante" rather than "quatre-vingt-dix", meaning "ninety". (We Belgians also say "septante" rather than "soixante-dix" for "seventy"; Swiss Francophones do the same.) I was unapologetic; it's not just local slang, it's officially written on my son's birth certificate ("L'année mille neuf cent nonante neuf", ie 1999).
I remember when Anne and I first visited Brussels on holiday, long before we moved here, and the bus driver told us the fare, moving from his own word to French French to Dutch/Flemish to English: "Septante! Soixante-dix! Zeventig! Seventy!" In how many other cities would a bus conductor know to ask for a fare in three and a half languages?