From Jim Breen's EDICT:
ワールドカップ, ダブルはい 【Ｗ杯】
What is most commonly used?
Is W ever pronounced the same as 'W' in English and not ダブル?
Will people ever say:
ダブルカップ?
ワールドはい?
I know everyone keeps refering to:
but that still doesnt answer my question if people ever just use the pronunciation of English 'W' to say Japanese 'W' - I mean there is a clear difference between W and ダブル.
Just from living in Japan, speaking to Japanese people, and more than anything consuming lots of Japanese media...
ワールドカップ is by far the most common.
だぶるはい I feel like should exist but I can't actually remember the last time I heard someone say this.
ダブルカップ, ワールドはい no.
If you need some extra evidence I found a chiebukuro post where the answers basically back me up that ワールドカップ is the most common.
1.ワールドカップ以外の読み方を聞いたことがありません。
2.基本どんな読み方でも悪くはないけどワールドカップって読む人が多いですよね～
3.サッカーとか知らないような人だったら、もしかして読むかも知れませんが、普通は読みません。というか、W杯って言葉なんですけど、何かに書いたりするような時に、ワールドカップという言葉を短縮するのには使ったりしますけど、会話ではワールドカップとは言いますけど、一般的にW杯とは会話では言いませんよね！？ etc etc
The pronunciation of W in Japanese is discussed here.
W杯 is not meant to be pronounced. No one knows how to say this out loud "correctly".
If conveying the meaning is important, I would read this as "ワールドカップ", maybe after one second of consideration. It's like saying "The First World War" for WWI.
If what's literally written on the paper is important, I would say "ダブリュー・はい", knowing this is an unusual way to refer to The World Cup. It's like saying "double-u, double-u, ai" for WWI.
The correct way to say "W", I believe, is ダブリュー. Announcers always say "ダブリュー、ダブリュー、ダブリュー、ドット、グーグル、ドット、コム" for "www.google.com".
I always pronounce W as ダブル only when it clearly means double, second, or extra (Wチャンス). But I hear many Japanese people say ダブル regardless of the context, probably because ダブル is easier to pronounce.
