The pattern
Put a trema on a vowel when it starts a new syllable and would otherwise melt with the vowel before it into one sound. Where two words of a compound meet, use a hyphen instead.
- The dots go on the vowel that starts the new syllable: ruïne, patiënt, geïnteresseerd. In ideeën and zeeën, that is the third e.
- Many plurals and numbers have one: ideeën, zeeën, knieën, tweeëntwintig.
- Prefixes such as ge- and be- are not words on their own, so words that start with them use a trema: geëmigreerd, beëindigen.
- In a compound, use a hyphen if the vowels where the two words meet could be read as one sound: zee-egel, auto-ongeluk, mee-eten. Otherwise, write the compound as one word: schoolboek, politieagent.
- No risk of melting, no mark: piano, radio, ideaal, Italiaans.
Examples
| Mijn buren gaan elk jaar naar België. | My neighbours go to Belgium every year. |
| Sanne heeft goede ideeën voor het feest. | Sanne has good ideas for the party. |
| Ben je geïnteresseerd in de cursus? | Are you interested in the course? |
| De patiënt zit in de wachtkamer. | The patient is sitting in the waiting room. |
| Daan wordt morgen tweeëntwintig. | Daan turns twenty-two tomorrow. |
| Yara heeft in Limburg een oude ruïne bezocht. | Yara visited an old ruin in Limburg. |
| Bas heeft een auto-ongeluk gezien. | Bas saw a car accident. |
| Carlos is tijdens zijn vakantie op een zee-egel gestapt. | Carlos stepped on a sea urchin during his holiday. |
| Wil je vanavond mee-eten? | Would you like to eat with us tonight? |
Why it works this way
Dutch reads vowel letters in teams. When you see ie, ei, ui or ee, you say one sound, as in drie, klein, huis and twee (more in vowel combinations). That is efficient, until two vowels meet by accident at the border between two syllables. Without dots, geinteresseerd would start like klein, and ruine would get the ui of huis. The trema says: these two are not a team.
Inside one word, two small dots are enough. When two complete words are glued together and their vowels could form a team, a hyphen is clearer, because you see both words at a glance: auto plus ongeluk. If the vowels cannot form a team, as in politieagent, the compound is simply written as one word. See writing compound words for the bigger picture.
As for the sound: it stays exactly what it would be without the dots. The ï in ruïne sounds like the i in piano; the ï in geïnteresseerd is the short i of in. The ë at the end of België and ideeën is the weak e of lopen (see the neutral e).
If you know German, forget the umlaut: German "ü" is a different sound from "u", but Dutch ë is just an e with a signal on top. English speakers have seen the same idea in naïve.
Remember: think of the two dots as a tiny pair of scissors. They cut the word at that vowel, and they never touch the sound.
Watch out
FalschIk ben geinteresseerd.
RichtigIk ben geïnteresseerd.
without dots, ei sounds like klein
Falschtwee ideeen
Richtigtwee ideeën
three e's in a row need a signal where the new syllable starts
Falschde patient
Richtigde patiënt
English spelling habit; without dots, ie sounds like drie
Falscheen autoongeluk
Richtigeen auto-ongeluk
oo would melt into one sound, so the compound gets a hyphen
Falscheen zeeëgel
Richtigeen zee-egel
the vowels meet where two words of a compound join: hyphen, not dots
Quick check
- Write the plural of the word in brackets: Mei heeft drie goede (idee).
- Choose: Ahmed is erg (geinteresseerd / geïnteresseerd) in voetbal.
- Fix the sentence: Joris heeft gisteren een autoongeluk gehad.
- One of these words needs a trema. Which one? piano, radio, Belgie
Antworten zeigen
- ideeën: ee plus en would melt together, so the third e gets the dots.
- geïnteresseerd: ge- is a prefix, so the word takes a trema, and ei must not sound like klein.
- Joris heeft gisteren een auto-ongeluk gehad.: auto and ongeluk form a compound, and oo would be read as one sound, so a hyphen.
- België: ie would sound like drie, while ia and io are not vowel teams in Dutch.
Use it today
Send a friend a short Dutch message about your weekend that uses three trema words, for example België, ideeën and geïnteresseerd. On a phone or a Mac, hold down the e or i key to find the letter with dots.