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I often see the alphabet `W` being transcribed or pronounced as "ダブル" rather
than "ダブリュー" in Japanese, and I think that in most cases, that was not what
was meant. Indeed, there seems to be a practice of abbreviating "ダブリュー" as
`W`, most often seen in a menu in a fast food restaurant, (whose meaning
intentionally or unintentionally goes along with the origin of `W` being "
**double** 'U' "), but even out of that context, I observe it being
transcribed/pronounced as "ダブル", and I don't know if people are doing it
because of the origin of the alphabet character `W`. Why do you think that
happens?
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2012-05-27T16:42:17.297
5642
2012-06-22T03:16:47.093
2012-05-27T19:44:36.623
question
loanwords
Pronunciation of W
I don't believe a definitive answer to your question is possible. That said,
you asked what people think, so a couple of my own thoughts:

When reading out URLs (arguably now the most common use of `W` in modern
Japanese), `ダブリューダブリューダブリュードット` would be a real mouthful, so it's often
pronounced `ダブルダブルダブルドット` or even `ダブダブダブドット`. It's possible that this has
contributed to the abbreviated pronunciation.

I don't know if you'll agree with this, but I find that the transliteration of
borrow-words is very prone to change and evolution over time for convenience
or what have you. The meaning "double" on fast food menus etc is probably the
second most common use of `W` in modern Japanese. Presuming this use came
first, this could also have influenced a change in the general pronunciation.

Alternatively, as you say, the English pronunciation of `W` comes from
`double-U`, so you could say the most "correct" transliteration would be not
`ダブリュー` but `ダブル・ユー`. `ダブル` would be a sane abbreviation of this, just like
many 和製英語 are informally abbreviated, purely for the sake of brevity.
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2012-05-27T22:00:14.807
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2012-05-27T22:00:14.807
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answer
I believe this may an example of what is called a volatile pronunciation. Take
a look at what is happening phonemically:  

  1. ダブリュー → ダブル
  2. /dabu **ɾjuː** / → /dabu **ɾu** /

Using the description in
[Vance(2008)](http://rads.stackoverflow.com/amzn/click/0521617545) of long
vowels:

> Japanese vowel length distinctions don't have a very high functional load;
> at any given point in a conversation mistakenly pronouncing a long vowel as
> a short vowel or vice versa is very unlikely to result in something that a
> listener could interpret as a plausible alternative utterance.

And most relevant to the above alternation:

> Word-final long vowels are conspicuously susceptible to shortening, although
> the explanation for this tendency isn't clear.

Vance gives two good examples of this:

  1. コンピューター → コンピュータ
  2. 本当 → ほんと

These facts would explain the long vowel drop of ダブリュー but doesn't yet account
for why the palatalization /j/ is also dropped in /ɾjuː/ → /ɾu/ since an
alternation of the form /ɾjuː/ → /ɾju/ would not result in a phonotactic
infringement.

I think one way to explain the /ɾjuː/ → /ɾju/ is by taking a risk and
generalizing or extrapolating Vance's implicit suspicions above to stipulate
that:

  1. Functional loads are a criteria in phonological processes. Namely, the lower the functional load the more susceptible to a (non-mandatory) phonological alternation 
  2. Word-final vowel shortening process can extend to certain semi-vowels. (Note that the palatalized /j/ of /ɾjuː/ is a semi-vowel)

Which, taking these as assumptions, the admissibility of /ɾjuː/ → /ɾju/ might
be predicated on:

  1. The alternation /ɾju/ → /ɾu/ has a low functional load
  2. Palatalized semi-vowels in word-final mora are in the class of semi-vowels referenced above

I would love for someone to comment with more insight on what Vance might be
alluding to. I suspect I just haven't read deep enough into Japanese
phonology.  
  
As for orthographic discrepancies, I truly cannot understand what you are
asking. Native orthographic transcriptions can be notoriously volatile, and is
of rather specialized concern. If you absolutely need an explicit
correspondence, I would just advice the following function:  
f({ダブル,ダブリュー})={W} with f-1({U})⊈{ダブル,ダブリュー}
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2012-06-22T03:16:47.093
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answer