W, or w, is the twenty-third and fourth-to-last letter of the modern English and ISO basic Latin alphabets. It typically represents a consonant, but in some languages it represents a vowel. Its name in English is double-u,[note 1] plural double-ues.[1][2]
History
A 1693 book printing that uses the "double u" alongside the modern letter; this was acceptable if printers did not have the letter in stock or the font had been made without it.
The classical Latin alphabet, from which the modern European alphabets derived, did not have the "W' character. The "W" sounds were represented by the Latin letter "V" (at the time, not yet distinct from "U").
The sounds /w/ (spelled ⟨V⟩) and /b/ (spelled ⟨B⟩) of Classical Latin developed into a bilabial fricative /β/ between vowels in Early Medieval Latin. Therefore, ⟨V⟩ no longer adequately represented the labial-velar approximant sound /w/ of Germanic phonology.
A letter W appearing in the coat of arms of Vyborg
The Germanic /w/ phoneme was therefore written as ⟨VV⟩ or ⟨uu⟩ (⟨u⟩ and ⟨v⟩ becoming distinct only by the Early Modern period) by the earliest writers of Old English and Old High German, in the 7th or 8th centuries.[3] Gothic (not Latin-based), by contrast, had simply used a letter based on the Greek Υ for the same sound in the 4th century. The digraph ⟨VV⟩/⟨uu⟩ was also used in Medieval Latin to represent Germanic names, including Gothic ones like Wamba.
It is from this ⟨uu⟩ digraph that the modern name "double U" derives. The digraph was commonly used in the spelling of Old High German, but only in the earliest texts in Old English, where the /w/ sound soon came to be represented by borrowing the rune ⟨ᚹ⟩, adapted as the Latin letter wynn: ⟨ƿ⟩. In early Middle English, following the 11th-century Norman Conquest, ⟨uu⟩ gained popularity again and by 1300 it had taken wynn's place in common use.
Scribal realisation of the digraph could look like a pair of Vs whose branches crossed in the middle. Another, common in roundhand, kurrent and blackletter, takes the form of an ⟨n⟩ whose rightmost branch curved around as in a cursive ⟨v⟩ (viz. {\displaystyle {\mathfrak {w}}.}{\displaystyle {\mathfrak {w}}.})[4][5] It was used up to the nineteenth century in Britain and continues to be familiar in Germany.[note 2]
The shift from the digraph ⟨VV⟩ to the distinct ligature ⟨W⟩ is thus gradual, and is only apparent in abecedaria, explicit listings of all individual letters. It was probably considered a separate letter by the 14th century in both Middle English and Middle German orthography, although it remained an outsider, not really considered part of the Latin alphabet proper, as expressed by Valentin Ickelshamer in the 16th century, who complained that:
Poor w is so infamous and unknown that many barely know either its name or its shape, not those who aspire to being Latinists, as they have no need of it, nor do the Germans, not even the schoolmasters, know what to do with it or how to call it; some call it we, [... others] call it uu, [...] the Swabians call it auwawau[6]
In Middle High German (and possibly already in late Old High German), the West Germanic phoneme /w/ became realized as [v]; this is why, today, the German ⟨w⟩ represents that sound.