So … what’s the deal with the double dots over the “i” in the word naïve—or over the “e” in Noël, Brontë, and Chloë? Is it simply an umlaut, which is used to change the vowel sounds of certain German words and is placed over the first vowel (e.g., Jägermeister, München)?
No, dear readers, it is not an umlaut; instead, the double dot over the “i” and “e” is a dieresis. Now you’re probably asking, “what the heck is a dieresis”? Your humble Scribe will explain.
A dieresis is used in English over the second of two consecutive vowels—e.g., naïve, Noël, and Chloë—to show that the vowels are pronounced as separate sounds, not as a diphthong. (A diphthong results when two consecutive vowels sounds are joined together to form one sound, e.g., deal, double, certain, pronounced.) A dieresis is also used to show that a final vowel is not silent, and should be pronounced—such as Brontë.
In the past, English had lots more words that included a dieresis, including coöperation and poëm. (Auto-correct really hates leaving a dieresis in those words, by the way.) But as people have learned to correctly pronounce these—and other—words that formerly had a dieresis, the dieresis was dropped.
That is all for now …