What Is a Diaeresis, and Why Do We Use It?

A listener named Al recently wrote in about our segment on the word “reenter.” Sometimes it’s written with a hyphen, and sometimes without.  

He suggested a third option: using the diaeresis. 

What is a diaeresis?

The diaeresis is a diacritical mark that looks like two little dots above a letter. It sometimes appears in English over the second of two consecutive vowels. If you’re familiar with German, you may have mistaken it for an umlaut since they look the same. The diaeresis’ job in English is to show that the second vowel is treated as a second syllable. Think of the long E in “Chloë,” for example, the second O in “coöperate,” or the I in “naïve.”

Diacritical marks in English

You’re probably thinking to yourself, “I’ve seen these words before, and they didn’t have any little dots in them.” 

That’s because the diaeresis, along with most diacritical marks, have fallen out of use in English. Take the word “hotel.” It came into English from French. It originally meant a mansion, and it originally had a pointy hat over the O; that is, an accent circumflex. That accent often appears in French over vowels after which an S used to appear. “Hôtel” used to be “hostel.” When the S went away over time, the circumflex over the O appeared. (1,2)

When “hôtel” came into English, it sometimes appeared with the accent, but that quickly disappeared. Have you ever seen “hotel” spelled with an accent? It’s rare.

Same with “résumé.” The Merriam-Webster dictionary shows the first reference of this word with an acute accent over both E’s. (An acute accent is a little dash tilted to the right.) However, plenty of people write the word "resume" without the accent marks, and three of the largest job portals on the web, LinkedIn, Monster, and Indeed, all avoid the accent marks.

And that make sense. Generally speaking, as foreign terms become naturalized into English, their accent marks fade away. That’s what’s happened with “hotel” and will likely happen with “résumé.” 

The origin of the diaeresis

That leads us back to the diaeresis. It had an important function back in the day. In fact, it was used in ancient Greece to separate a vowel at the start of a new word from a vowel at the end of a preceding word. That was important because Greek used to be written without any spaces between words! So that diaeresis—which comes from the Ancient Greek word for “division”—was really essential! (3)

While we’re...

Keep reading on Quick and Dirty Tips