Dutch has four main diphthongs (tweeklanken) that cause consistent trouble for English speakers. The ij/ei diphthong (these two spellings represent the same sound) appears in words like zijn (to be), mijn (my), trein (train), hij (he), tijd (time). It begins with a mid-front vowel (like e in bed) and glides toward the j (y) position. Many learners produce it too close to English eye — the Dutch version starts lower and does not open as wide.
The ui diphthong (huis — house, uit — out, buiten — outside, ruim — spacious) is the most uniquely Dutch sound. It begins with a rounded front vowel (like eu in neus) and glides toward a schwa. There is genuinely no English equivalent. The key: lips must be rounded at the start. If your ui sounds like English ow (as in how), you are starting unrounded — add lip-rounding and the sound will shift toward authentic Dutch ui.
The ou/au diphthong (oud — old, blauw — blue, goud — gold, vrouw — woman) sounds similar to English ow in how or out. The Dutch version starts slightly more open. This is the most accessible Dutch diphthong for English speakers. Finally, the ei in certain words like lei (slate) is identical to ij. Minimal pairs that help distinguish diphthongs: huis (house) vs hoes (case/cover), tijd (time) vs toed (unknown — not a word, so use contrasts in real word pairs like bij-bui, mijn-mun).