The title says it all! Even if Anglo doesn't quite mean "of the English" you get what I mean.
Learn English – If the prefix anglo- means “of the English”, what prefix means “of the Welsh”
prefixes
Related Solutions
I don't think that it's the same prefix as much as it is the remnant of a number of different grammaticalised pre-fixings. Most of them seem to have happened during the period when then curious admixture of French, Viking Danish, Anglo-Saxon and a sprinkling of Gaelic were distilling themselves down into the various dialects of Middle English. The spelling's kind of arbitrary, but a is the letter we tend to use when a word starts with a schwa that's flatter than we'd represent with a short e.
English was essentially an unwritten language during that period (and the population essentially illiterate), so it could be a time of great flux. A lot of words were repartitioned. All one became alone, the n sound migrated from the ends of words like mine and thine to become the initial (and previously non-existent) consonant of words (especially eke names -- thine eke name also became thy nickname) and so on.
As with a lot of what happened during this period, what we have now in the language is mostly what was present in and around London when the orthography was fixed by printing. Many of the a- words that one recognises as quaint regionalisms today (like a-hunting) were standard in dialects that did not, themselves, have the good fortune to become the standard themselves.
As for new words, well, printing (and general literacy) sort of put a stop to arbitrary movement of word boundaries. A question was posted here earlier asking about the meaning of "grab a hold", and it didn't take long for somebody to reply that the phrase was actually "grab ahold" (something my spell checker has decided is a problem). I would bet that "grab a hold" or "take a hold" (hold being synonymous with handle, as preserved in hand-hold) was the original phrase. They sound the same, and if you hear a hold often enough without seeing it written down, there's no real reason why you might not think of them as a single word.
In short:
- In Proto-Germanic, the prefix was *ga-;
- In Old English, it was ġe- (pronounced /je/, /jə/);
- In Middle English, it was y-, i-, or ȝe- (pronounced /ɪ/);
- In Modern English, it survives in a handful of words as i-, a-, or y- (see below).
The Wiktionary page for y- has these usage notes:
This prefix represents a common Germanic perfective prefix which was used to form past participles. Already by the Old English period such participles could be used with or without it, and as it passed into Middle English forms y-, i-, and ȝe-, it became less productive. The prefix was later adopted as a conscious archaism by some writers such as Edmund Spenser, who prepended it to existing past participles.
Etymonline has this to say about y-:
perfective prefix, in y-clept, etc.; a deliberate archaism, introduced by Spenser and his imitators, representing an authentic M.E. prefix, from O.E. ge-, originally meaning "with, together" but later a completive or perfective element, from P.Gmc. *ga-. It is still living in German and Dutch ge-, and survives, disguised, in some English words (e.g. alike, aware, handiwork).
Finally, the Merriam-Webster has this discussion of yclept:
"Clepe" itself is a word that is considered archaic and nearly obsolete, but its past participle "yclept" (pronounced ih-KLEPT) continues to be used, albeit rarely. In Old English, the prefix "ge-" denoted the completion or result of an action; in Middle English, the prefix shifted to "y-" and appeared in words such as "ybaptised" and "yoccupied." Eventually, all the "y-" words except "yclept" fell into disuse. One reason that "yclept" persists may be that it provides a touch of playfulness that appeals to some writers. Another may be that although "yclept" is an unfamiliar term to most people, its meaning can usually be inferred from context. Whatever the reason, "yclept" continues to turn up occasionally in current publications despite its strange and antiquated look.
Emphasis mine in all cases.
And yes, I realize that I haven't addressed the why part of your question.
Best Answer
Cambro- is the traditional form; the OED defines it in part as:
It’s never been common, but has clung on tenaciously over the years, in cambrophone, cambro-centric, Cambro-American, and the like. (It’s much more common in geological use, where it refers to the Cambrian Period.)
However, few apart from classicists or historians will understand it. An alternative option is Cymru- or Cymro-. This is less traditional, but usage on the internet and in British newspapers suggests it’s probably about as common today; and it has the great advantage that most Brits, and certainly anyone who’s lived in or near Wales, will understand it immediately. So if you don’t mind creating etymological Frankensteins, this is what I’d recommend.