英语词源字典 - 在线词源网站

D [D 词源字典]: fourth letter of the Roman alphabet, from Greek delta, from Phoenician and Hebrew daleth, pausal form of deleth "door," so called from its shape. The sign for "500" in Roman numerals. 3-D for "three-dimensional" is attested from 1952.[D etymology, D origin, 英语词源]
Q: 16th letter of the classical Roman alphabet, from the Phoenician equivalent of Hebrew koph, qoph, which was used for the more guttural of the two "k" sounds in Semitic.

The letter existed in Greek, but was little used and not alphabetized; the stereotypical connection with -u- began in Latin. Anglo-Saxon scribes adopted the habit at first, but later used spellings with cw- or cu-. The qu- pattern returned to English with the Norman Conquest and had displaced cw- by c. 1300. In some spelling variants of late Middle English, quh- also took work from wh-, especially in Scottish and northern dialects, for example Gavin Douglas, Provost of St. Giles, in his vernacular "Aeneid" of 1513:
Lyk as the rois in June with hir sueit smell
The marygulde or dasy doith excell.
Quhy suld I than, with dull forhede and vane,
With ruide engine and barrand emptive brane,
With bad harsk speche and lewit barbour tong,
Presume to write quhar thi sueit bell is rong,
Or contirfait sa precious wourdis deir?
Scholars use -q- alone to transliterate Semitic koph (as in Quran, Qatar, Iraq ). In Christian theology, Q has been used since 1901 to signify the hypothetical source of passages shared by Matthew and Luke, but not in Mark; in this sense probably it is an abbreviation of German Quelle "source."
W: not in the Roman alphabet, but the Modern English sound it represents is close to the devocalized consonant expressed by Roman -U- or -V-. In Old English, this originally was written -uu-, but by 8c. began to be expressed by the runic character wyn (Kentish wen), which looked like this: ƿ (the character is a late addition to the online font set and doesn't display properly on many computers, so it's something like a combination of lower-case -p- and a reversed -y-). In 11c., Norman scribes introduced -w-, a ligatured doubling of Roman -u- which had been used on the continent for the Germanic "w" sound, and wyn disappeared c. 1300. -W- is not properly a letter in the modern French alphabet, and it is used there only in borrowed foreign words, such as wagon, weekend, Western, whisky, wombat.
abecedarium: "The alphabet; especially (in early use) the Roman alphabet as opposed to the Greek; (in later use) an alphabet belonging to an ancient writing system, or an inscription of this", Old English; earliest use found in Byrhtferð of Ramsey (fl. c986–c1016), Benedictine monk and scholar. From post-classical Latin abecedarium abecedary; compare -arium.