Most Semitic scholars transliterate waw as a "w" or a "u", depending on school and pronunciation. Vav and the use of V, did not originate till later. When Eliezer Ben Yehuda, the father of modern Hebrew, was reviving Hebrew in the late 1800's and early 1900's, so that a nation could be established, he tried to avoid the Ashkenaz dialect as much as possible, preferring the Sephardic. "The Ashkenazic variety of Hebrew reminded the Council too much of Yiddish, the despised language of the Exile in the opinion of most of the Council's members, which in particular, contained the same set of vowel phonemes. Conversely, the Sephardic form resembled the sound pattern of Arabic more closely and Arabic was the sister language in the Semitic family which already existed in the locale." The Revival of a Classical Tongue, Eliezer Ben Yehuda and the Modern Hebrew Language, Jack Fellman, Pg. 84. Ben Yehuda was greatly influenced by Arabic and Aramaic, in his modernizing Hebrew as a spoken language and not just liturgical. Though the Council and Ben Yehuda devised a system for the Hebrew, which more closely resembled the Biblical and Sephardic, what emerged was that of the Ashkenaz, as a result of the increasing amount of Eastern European immigrants. They were the ones to teach the children in the kibbutzim and that is what became the dominant language. The use of vav, is Ashkenaz and Yiddish.
In the early texts of the English Bible, they spell Dawiyd as Dauid. Which is the same way that the Septuagint writes it in Greek. The ui vowel combination, a diphthong, makes the wee sound as in French oui. Dawiyd is pronounced Da-wiyd or Da-weed.
"Both Hebrew pronunciation and Hebrew vocalization thus underwent various phases of development until they reached their present day stage." "The influences of external factors: How can we account for the present day twofold pronunciation of the letters Beyth, Kaf, Fe, and Thau among so large a segment of Jewry, a pronunciation which has no foundation at all in the ancient and genuine Hebrew sources? " "According to an explicit statement by Jerome (cf. TRL, paragraph XXIII under Fe), Hebrew had no 'p' sound at all; and implicitely all the trasliterations and other pertinent evidence (cf. Here 44ff) available agree on the fact that even Beth, Kaf and Thau, irrespective of their position (whether initial, medial or even final place) as well as Shiyn had only one consonantal value each (cf. TRL paragraph XXIII under those letters). Their twofold pronunciation was brought about by way of a Differentiating Dot. The reason for it must have been the languages of the 'Wirtsvoelker': the nations, in whose midst the Jews lived, had in their respective languages corresponding sounds, which heretofore had been alien to the Hebrew speech. " Pre-Masoretic Bible, Alexander Sperber, Pg. 26
"With regard to their origin and diffusion, linguistic changes correspond to the absence or presence of foreigners and to the extent of commercial and political relations between the different areas. Some chages, however, took place independently in different dialects." A History of the Hebrew Language, Angel Saenz-Badillos, Pg. 46.
"The situation today makes it possible to conclude that at an early stage w came to be pronounced v, possibly while the Samaritans still spoke Hebrew, and since it coalesced with fricative Beth, it was included with the process of fricative/plosive interchange, together with Beth, Fe, Daleth, Waw and Thau." A Grammar of Samaritan Hebrew, Zeev Ben-Hayyim, pg. 33.
"The Samaritan tradition in Samaritan Hebrew and Samaritan Aramaic concerning the articulation of Waw is clear evidence of a w>v process in Palestine, at least during the period of Aramaic speech.13" Ibid, pg. 34
Footnote 13, "See Ben-Hayyim, Studies, 105. Pronouncing the waw as v is undoubtedly the reason for the beth/waw interchange in manuscripts in Rabbinic literature. "
Arabic's waw is a w/u, just as in the older Hebrew and Samaritan Hebrew. They, like Greek, do not have a vav. Some scholars have theorized that the v came with the Indo-European languages that derived from Sanskrit, which does have a v. Another similarity between the Ancient Hebrew, Samaritan is that of the Shiyn. In both, shiyn is always a Sh. The Samek was the S. Later Hebrew took to placing a dot over the right side of the shiyn for Sh and a dot over the left side for S. A good example of this is Shibboleth, the word that caused the death of those that could not pronounce it properly (Shoftiym [Judges] 12:6). When Shibboleth is written, it is Shiyn, but when Sibboleth is written, it is Samek. The same occurred with Thau and Teyt.
The letter Waw was also adopted by the Greeks, from the Phoenicians. The intersecting portion on top, similar to our Y, was curved on top, like an open semi-circle. This became the Greek letter Upsilon about 600 BCE. Sometimes it is written as a Y and sometimes as a U. The lowercase letter is written as a u. This was also adopted by the Romans, from the Greeks. The Romans gave the letter its capital V shape about 114 CE. Medieval scribes wrote two VV’s together about 1000 CE. VV was also written UU and the letter came to be known as the “double U”, written as W. Medieval scribes used the V for a consonant and used the U for a vowel. The development of W and U was very similar to the development of I and J.
The early alphabets did not have a letter “J”. First, you have Proto-Canaanite script. From that descended the paleo-Arabic, paleo-Aramaic, paleo-Hebrew, and the paleo-Phoenician. The Archaic Greek, descends from the Phoenician. And the Latin, descends from the Greek. In time it changed to one more upright and with a slight curve to the bottom, instead of a sharp angle, about 1000 BCE. The Greeks made the letter a single, vertical stroke about 600 BCE. They named the letter an Iota. It makes the same Y sound of Yod, as a consonant, but also makes an I sound, as in index. The Romans gave the “I” its capital form about 114 CE. When “I” was the initial letter in a word, they began making an ornamental, descending stroke to the left. This began in the 1200’s and became popular in the 1500’s. Generally the initial sound of I was as a consonant. Eventually, the Letter J came to denote the Y sound and I the I sound. The letter J became different from the I, in 1630, in England.
With the development of the letter J and the European use of the letter V for Waw, the corrupted spelling of Iehowah, became Jehovah.
There are several accounts to when the first use of Jehovah began. “But in the Middle Ages certain Christian theologians (the first known is Raymond Martin in 1270), copying the voweled tetragrammaton in transliteration, spelled it out to read JeHoVaH.” (The Universal Jewish Encyclopedia, 1905, Jehovah, Pg. 55) “The pronunciation indicated by ‘Jehovah’ (J being pronounced as Y) has been traced as far back as Wessel (d. 1489), who used Johavah and Jehovah, and Petrus Galatinus, confessor of Leo X. (1513-21).” (The New Schaff-Herzog Encyclopedia of Religious Knowledge, Yahweh, pg. 470) In 1516, Pietro Columna Galatinus (1460-1540), Pope Leo 10th’s confessor, wrote a book titled, “De Arcanis Catholicae Veritatis (Concerning Secrets of Universal Truth). In his book, written in Latin, he introduces the spelling of Jehovah. “It was contested by other scholars as being against grammatical and historical propriety”. (Oxford English Dictionary, Jehovah. Encyclopedia Judaica, Galatinus.)
In Biblical Hebrew, Samaritan Hebrew Waw was a W/U. Greek did not have a V, neither did Akkadian, Arabic or Ethiopic, Waw is W. An old Persian syllabary, in cuneiform, has a wa and a wi, but no v's, yet later Persian did.
No language on earth has remained intact over hundred and thousands of years. Hebrew is no different, contrary to the belief of those that Hebrew is some sacred tongue protected by YHWH from change and that the Hebrews have faithfully preserved it. Hebrew is just a human tongue and has gone through many changes. We may never know all of them, but we can open our eyes and realize what changes are available to us and learn from them.