U derives from the Semitic waw, as does F, and later, Y, W, and V. Its oldest ancestor goes to Egyptian hieroglyphics, and is probably from a hieroglyph of a mace or fowl, representing the sound [v] or the sound [w]. This was borrowed to Phoenician, where it represented the sound [w], and seldom the vowel [u].
In Greek, two letters were adapted from the Phoenician waw. The letter was adapted, but split in two, with the first one of the same name (Ϝ) being adapted to represent [w], and the second one being Upsilon (Υ), which was originally adapted to represent [u], later fronted, becoming [y].
In Latin, a stemless variant shape of the upsilon was borrowed in early times as U, taking the form of modern-day V — either directly from the Western Greek alphabet or from the Etruscan alphabet as an intermediary — to represent the same /u/ sound, as well as the consonantal /w/, num — originally spelled NVM — was pronounced /num/ and via was pronounced [ˈwia]. From the 1st century AD on, depending on Vulgar Latin dialect, consonantal /w/ developed into /β/ (kept in Spanish), then later to /v/.
During the late Middle Ages, two forms of U developed, which were both used for /v/ or the vowel /u/. The pointed form 'V' was written at the beginning of a word, while a rounded form 'U' was used in the middle or end, regardless of sound. So whereas 'valour' and 'excuse' appeared as in modern printing, 'have' and 'upon' were printed 'haue' and 'vpon', respectively. The first recorded use of 'U' and 'V' as distinct letters is in a Gothic alphabet from 1386, where 'V' preceded 'U'. Printers eschewed capital 'V' and 'U' into the 17th century and the distinction between the two letters was not fully accepted by the French Academy until 1762.[3] The rounded variant became the modern-day version of U and its former pointed form became V.
Pronunciation and use
Pronunciations of Uu
Languages in italics do not use the Latin alphabet; the table refers to latinizations
Pronunciation of the name of the letter ⟨u⟩ in European languages
English
In English, the letter ⟨u⟩ has four main pronunciations. There are "long" and "short" pronunciations. Short ⟨u⟩, found originally in closed syllables, most commonly represents /ʌ/ (as in 'duck'), though it retains its old pronunciation /ʊ/ after labial consonants in some words (as in 'put') and occasionally elsewhere (as in 'sugar'). Long ⟨u⟩, found originally in words of French origin (the descendant of Old English long u was respelled as ⟨ou⟩), most commonly represents /juː/ (as in 'mule'), reducing to /uː/ after ⟨r⟩ (as in 'rule'), ⟨j⟩ (as in 'June') and sometimes (or optionally) after ⟨l⟩ (as in 'lute'), and after additional consonants in American English (see do–dew merger). (After ⟨s⟩, /sjuː, zjuː/ have assimilated to /ʃuː, ʒuː/ in some words) In a few words, short ⟨u⟩ represents other sounds, such as /ɪ/ in 'business' and /ɛ/ in 'bury'.
The letter ⟨u⟩ is used in the digraphs ⟨au⟩/ɔː/, ⟨ou⟩ (various pronunciations, but usually /aʊ/), and with the value of "long u" in ⟨eu⟩, ⟨ue⟩, and in a few words ⟨ui⟩ (as in 'fruit'). It often has the sound /w/ before a vowel in the sequences ⟨qu⟩ (as in 'quick'), ⟨gu⟩ (as in 'anguish'), and ⟨su⟩ (as in 'suave'), though it is silent in final -que (as in 'unique') and in many words with ⟨gu⟩ (as in 'guard').
Additionally, the letter ⟨u⟩ is used in text messaging, Internet and other written slang to denote 'you', by virtue of both being pronounced /juː/.
One thing to note is that certain varieties of the English language (i.e. British English, Canadian English, etc.) use the letter U in words such as colour, labour, valour, etc.; however, in American English the letter is not used and said words mentioned are spelled as color and so on. It is the thirteenth most frequently used letter in the English language, with a frequency of about 2.8% in words.
Other languages
In most languages that use the Latin alphabet, ⟨u⟩ represents the close back rounded vowel/u/ or a similar vowel.[6]
U is also the source of the mathematical symbol ∪, representing a union. It is used mainly for Venn diagrams and geometry.
It is used as for micro- in metric measurements as a replacement for the Greek letter μ (mu), of which it is a graphic approximation when that Greek letter is not available, as in "um" for μm (micrometer).
^"U", Oxford English Dictionary, 2nd edition (1989); Merriam-Webster's Third New International Dictionary of the English Language, Unabridged (1993)
^Brown & Kiddle (1870) The institutes of English grammar, page 19. Ues is the plural of the name of the letter; the plural of the letter itself is rendered U's, Us, u's, or us.
