The short answer

The letter "W" is called "double u" because it was originally formed by placing two "U" letters side by side to represent the "wuh" sound in Old English, which adapted the Latin script. Although "W" looks like two "V" letters, its name reflects its historical writing as "UU," influenced by the evolution of the English alphabet and Latin alphabet development.

The long answer

In classical Latin, the alphabet didn't have a "U" or "W" symbol; instead, they used "V" for both the vowel and consonant sounds "uh" and "wuh." For example, Augustus was written as "Avgvstvs," and the word "Volcanvs" was pronounced "wolcanus." Over time though, the "wuh" consonant use of the "V" letter transitioned into the "vee" sound we know today. This evolution of letter pronunciation is a significant part of the history of the English alphabet.

Then, around the 8th century, Germanic languages like Old English started to be written using the Latin script. Since the Latin alphabet no longer had a symbol to demonstrate the "wuh" sound, Old English writing combined two "U" symbols side-by-side to create the "wuh" sound. They didn't combine two "V"s because "V" was not a letter used in Old English. By the 14th century, people were writing "UU" so often that it became a symbol on its own: "double u."

So the origin of the letter "W" comes from combining two "U" letters together. But why is it pronounced "double u" and not "double v"? The history is a bit fuzzy but centers around the advent of the printing press.

• First, the "V" letter was commonly used for "U" use cases, so it's understandable that these were considered fairly interchangeable.

• Additionally, the singular type block for "UU" was less common, so printers often used two "V" letter blocks in place of the less common "UU." This practical decision by early printers contributed to the shape of "W" resembling two "V"s.

• Finally, there may have been some desire to stick with ancient Roman inscription traditions of using "V" over "U" (recall "Avgvstvs").

The TL;DR is "V" and "U" have a very intertwined letter history, and Old English didn't use a "V" letter, so they combined two "U" letters together to create the "wuh" sound. Then the printing press solidified the letter design as a double v, but the name "double u" stuck.

🧠 Bonus brain points

In many other languages such as French, Spanish, Italian, Danish, Norwegian, and Swedish, the letter "W" is pronounced as "double v." This is due to the influence of their respective alphabet development histories, where "V" and "U" have been treated differently than in English.

Sources

Dictionary.com. (2020, June 15). What does the letter "U" have to do with "W"? Dictionary.com. Retrieved December 30, 2022, from https://www.dictionary.com/e/w/

Neeson, J. (2022, November 27). This Is Why “W” Is Pronounced Double U and Not Double V. Reader's Digest. Retrieved December 30, 2022, from https://www.rd.com/article/why-w-is-pronounced-double-u-and-not-double-v/

O'Conner, P. T., & Kellerman, S. (2022, April 20). Why isn’t a W called a double V? Grammarphobia. Retrieved December 30, 2022, from https://www.grammarphobia.com/blog/2011/04/double-u.html

Philologism. (2021). Why is W called Double-U? Retrieved December 30, 2022, from https://www.youtube.com/watch?v=h9qrOxFptoc.