Belgian Dutch (Flemish) and Netherlandic Dutch differ most noticeably in pronunciation, less so in grammar, and somewhat in vocabulary. The most striking phonological difference is the soft G in Flemish vs. the hard G in the Netherlands. Flemish G is breathy, almost like the French J — and much easier for English speakers to produce. If you are learning Dutch for Belgium or simply prefer a softer sound, the soft G is entirely acceptable and natural.
Vowel differences: Flemish Dutch tends to preserve longer, more clearly articulated vowels compared to the Netherlands, where vowels are often reduced and clipped. The Flemish ui and ij may sound slightly different from the Randstad equivalents. Intonation in Belgium tends to be more melodic and rising at the end of statements — which to a Netherlandic ear can sound like a question. This intonation difference is one of the most immediately recognizable features distinguishing Belgian from Dutch speakers.
Vocabulary and politeness register: Belgian Dutch uses u (formal you) more widely than the Netherlands, where jij has become dominant in most contexts. Belgian Dutch retains more formal register vocabulary in everyday use. Alstublieft is used more frequently in Belgium; in the Netherlands, alsjeblieft or even just a smile has replaced it in many interactions. Understanding these differences makes you more versatile and culturally sensitive when communicating across the Dutch-speaking world.