The two dots on _ë_ and _ï_ are called a trema (_het trema_), and they have one job: they tell you that a new syllable (a beat in a word) starts at that vowel. So _België_ is _Bel-gi-ë_, not _Bel-gie_. In a compound (a word built from two words), a hyphen does the same job when two vowels meet, as in _zee-egel_. Neither mark changes how the letter itself sounds.
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](#/lesson/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](#/lesson/compound-spelling) 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](#/lesson/schwa-and-endings)).
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
- Not: _Ik ben geinteresseerd._ Say: _Ik ben geïnteresseerd._ (without dots, _ei_ sounds like _klein_)
- Not: _twee ideeen_ Say: _twee ideeën_ (three e's in a row need a signal where the new syllable starts)
- Not: _de patient_ Say: _de patiënt_ (English spelling habit; without dots, _ie_ sounds like _drie_)
- Not: _een autoongeluk_ Say: _een auto-ongeluk_ (_oo_ would melt into one sound, so the compound gets a hyphen)
- Not: _een zeeëgel_ Say: _een 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_
Answers
- _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.