西班牙语里边，W就是读成uve doble（一对儿V），而不是“一对儿U”，

从其他方面来看
1、W是辅音，要把它分解（或者说它的来源），也应该是辅音V而不是原音U。

2、从写法看，W下边的两个头儿是尖的，而不是圆的，所以，应该是两个V组成的，而不是两个U组成的。

至于它在英语中的读音，我记得听美国人英国人读成打不溜或打不油的都有，似乎都是正确的。

维基给的：W (play /ˈdʌbəljuː/, /ˈdʌbəjuː/, /ˈdʌbəjə/, or /ˈdʌbjə/;

以下为引用：

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维基百科：

W, w 是拉丁字母中的第23个字母。

W由盎格鲁撒克逊人在7世纪发明，起初用来表示两个U（double U，意即“两个U”）。拉丁语中的／w／发展成为罗曼语中的／v／，因此V不再完全表示日尔曼语族中的／w／ ，在法语，w 称为 doublé v，除外来语外，多数表示／v／音。在西班牙语，此字母称为 uve doble 或 doble ve 。德语中的 W 也像在罗曼语系中一样丢失了，这就是为什么德语的W表示／v／而不是／w／。在荷兰语中，W是一个通音（除了带有eeuw的词语，发作[-e:w]）。

在瑞典语和芬兰语字母表中，W被看作V的变体而不是一个独立的字母。但是仍然保持在名字中并获得承认，例如“William”。

History
The sounds /w/ (spelled with ‹V›) and /b/ (spelled ‹B›) of Classical Latin developed into a bilabial fricative /β/ between vowels in Early Medieval Latin. Therefore, ‹V› no longer represented adequately the labial-velar approximant sound /w/ of Germanic phonology.

The Germanic /w/ phoneme was therefore written as ‹vv› (a doubled) v, or, equivalently (‹u› becoming distinct from ‹v› only by the High Medieval period), ‹uu› (a doubled u) by the 7th or 8th century by the earliest writers of Old English and Old High German.[5] Gothic, by contrast, simply used the Greek Υ for the same sound.

It is from this ‹uu› digraph that the modern name "double U" derives. The digraph was commonly used in the spelling of Old High German, but only sporadically in Old English, where the /w/ sound was usually represented by the runic wynn (‹Ƿ›). In early Middle English, following the 11th-century Norman Conquest, ‹uu› gained popularity and by 1300 it had taken wynn's place in common use.

Scribal realization of the digraph could look like a pair of Vs whose branches crossed in the middle. An obsolete, cursive form found in the nineteenth century in both English and German was in the form of an "n" whose rightmost branch curved around as in a cursive "v".[citation needed] The shift from the ligature ‹vv› to the distinct letter ‹w› is thus gradual, and is only apparent in abecedaria, explicit listings of all individual letters. It was probably considered a separate letter by the 14th century in both Middle English and Middle German orthography, although it remained an outsider not really considered part of the Latin alphabet proper, as expressed by Valentin Ickelsamer in the 16th century, who complained that

"Poor w is so infamous and unknown that many barely know either its name or its shape, not those who aspire to being Latinists, as they have no need of it, nor do the Germans, not even the schoolmasters, know what to do with it or how to call it; some call it we, [... others] call it uu, [...] the Swabians call it auwawau"[6]

In Middle High German (and possibly already in late Old High German), the West Germanic phoneme /w/ became realized as [v]; this is why the German ‹w› today represents that sound. There is no phonological distinction between [w] and [v] in German and the [w] sound remains heard allophonically for ‹w›, especially in the cluster ‹schw›, besides [kw] for ‹qu›.

In Dutch it became a labiodental approximant /ʋ/ (with the exception of words with -‹eeuw›, which have /eːβ/, or other diphthongs containing -‹uw›). Dialectally, in many Dutch speaking areas, such as Flanders and Suriname, the /β/ pronunciation is used at all times.