Why do Belgian Dutch speakers say “u” to family members?

Belgian Dutch (Flemish) keeps u alive in family and friend talk in a way Netherlands Dutch doesn’t. North of the border, u is almost purely formal, reserved for strangers and authority figures, while je covers everyone close. South of the border, in Flanders, an aunt, an uncle, even a parent often gets u without any cold feeling. The pattern echoes the formal-familiar split you find in French, German, and Spanish, but Flemish u sits in a softer middle: respectful, warm, family-shaped. Dutch grammar guides label it the gij/u paradigm, the older Southern Netherlands pronoun system.

In this clip, a young Flemish woman in a busy café tells an older relative, “Ik weet niet wat onkel Jan u gisteren gezegd heeft.”