Diaeresis: what is it and when should it be used?

By Marta Díaz on Thursday, March 6, 2025

Have you ever found two points over a vowel while reading in Spanish? You may have seen a “u” with a diaeresis in certain words, but do you know what it means or when it should be used?

This linguistic phenomenon is called the diaeresis (¨) and has an important function in pronunciation. Unlike in English, where the diaeresis is very rare and is mainly found in old or formal texts (as in coöperate or naïve), in Spanish it has a specific and necessary use in certain words.

Below, we explain what the diaeresis is, when and why it is used in Spanish.

What is diaeresis?

The diaeresis is an orthographic symbol, represented by two small dots, which are placed over a vowel, specifically over the “u”, in certain syllables (“gue” and “gui”) to indicate that this vowel is pronounced.

Normally, in words like “guerra” (war) or “guitarra” (guitar), the vowel u is silent. However, when the diaeresis is added, it indicates that the u should be pronounced as an independent sound.

Here are some examples of words with diaeresis:

• Pingüino (penguin): it is pronounced peeng-GWEE-no (the 'u' is sounded)
• Lingüística (linguistics): pronounced leen-GWEE-stee-ka
• Vergüenza (shame): pronounced ver-GWEN-tha (Spain) or ver-GWEN-sa (Latin America)

Without the diaeresis, these words would be pronounced incorrectly according to the phonetic rules of Spanish.

Why is the diaeresis important?

The diaeresis in Spanish guarantees correct pronunciation and helps to differentiate words. If it is omitted, a Spanish speaker could mistakenly apply the general rule where the syllables “gue” and “gui” have a silent “u”.

Generally, Spanish speakers omit this vowel in words, which is why the diaeresis is necessary, to know when to pronounce the u and when not to. For example: “guitarra” does not have a diaeresis because the u is silent and the “i” carries more weight. Whereas in “amortigüe” the u is pronounced since otherwise the word would sound phonetically wrong.

Like any other orthographic sign in Spanish, the diaeresis has certain rules when it comes to its use:

• It always goes on the vowel “u”. It is never used on any of the other vowels or on consonants.
• It always starts with “g”. The diaeresis can only be used in syllables that begin with the consonant “g”.
• It is always followed by the vowels “e” or “i”. The diaeresis must always be in a syllable that ends in “e” or “i”
• It is always written. No matter what the word is, the diaeresis is always written.
• The syllable is almost always stressed. When diaeresis is used, the syllable that carries it is stressed, although there are exceptions. E.g. pingüino (penguin).

In addition to Spanish, there are other languages that also use the diaeresis. Among them we find:

• German (Umlaut: ä, ö, ü): changes the sound of the vowel. g. Mädchen (girl), über (on)
• French (Tréma: ë, ï, ü): indicates that the vowels are pronounced separately. E.g. Noël (Christmas), naïve (naive)
• Dutch: separates vowels in compound words. E.g. coördinatie (coordination)
• Turkish: distinguishes between different vowels. E.g. gün (day), söz (word)

Examples of words in Spanish with diaeresis

Below you will find sentences with Spanish words that carry diaeresis:

• El pingüino caminaba torpemente sobre el hielo (The penguin walked awkwardly on the ice)
• Me encanta estudiar lingüística porque me ayuda a entender los idiomas (I love studying linguistics because it helps me understand languages)
• Sentí mucha vergüenza cuando me caí en medio de la calle (I felt very embarrassed when I fell in the middle of the street)
• La ambigüedad de su respuesta nos dejó con más dudas (The ambiguity of his answer left us with more doubts)
• El bilingüismo es una gran ventaja en el mundo laboral (Bilingualism is a great advantage in the labor market)
• La cigüeña es un ave migratoria que recorre largas distancias (The stork is a migratory bird that travels long distances)
• En México, llaman güero a las personas de piel clara o cabello rubio (In Mexico, people with fair skin or blond hair are called güeros)
• Prefiero el güisqui con hielo en lugar de tomarlo solo (I prefer whiskey on the rocks to straight whiskey)
• El agua no pasaba bien por el desagüe porque estaba atascado (The water didn't go down the drain properly because it was blocked)
• Guardé mi paraguas en el paragüero de la entrada (I kept my umbrella in the umbrella stand at the entrance)

In addition to some words such as “pingüino” (penguin) or “vergüenza” (shame), some verb conjugations ending in -guar also require diaeresis. For example: “averigüé” or “agüé”. On the other hand, the verb “argüir” (to argue) loses the diaeresis when it is conjugated: “yo arguyo”, “ellos arguyeron” or “nosotros arguyamos”.

Although these are some of the most common, there are other words with umlauts in Spanish that do not appear in our example sentences, such as “zarigüeya”, “ungüento” or “lengüeta”. So, although the diaeresisis not very common in Spanish, it is essential for the correct pronunciation of words with the syllable “gue” and “gui”; and it appears in more words than you think.

Understanding this small but important symbol will help you sound more natural and avoid pronunciation mistakes. Keep practicing and learn Spanish in Spain to master all the Spanish words with accents.