You’re right, Jayson, I may have been a little too technical, I’m sorry. As per your request, I’ll try to clarify everything with some examples.
The sound /w/ is the sound of w in ‘water’ (Pgmc. *watar), ‘wine’ (Pgmc. *winam < Lat. vīnum) etc, and is the original sound in all Germanic languages:
Pgmc: *watar, *winam;
Gothic: wato, wein
OE: wæter, wīn;
OFris: wetir, wīn;
OS: water, wīn;
OHG: wazzar, wīn.
ON: vatn, vīn (the evolution took place earlier in the North Germanic Languages)
Please, note that the sound /v/ didn’t exist in classical Latin. The letter v sounded Like /u/ or /w/, so ‘vinum’ sounded approximately like /wi:num/, not /vi:num/. In vulgar Latin, above sounds gradually evolved into /v/, which is the phonetic value in use in all Romance languages.
In the course of their evolution, in all Germanic languages, except English, the sound /w/ evolved into /v/:
English: water, wine
West Frisian: weter, wyn;
Dutch: water, wijn;
German: Wasser, Wein;
Icelandic: vatn, vín;
Danish: vand, vin;
Swedish: vatten, vin;
Norwegian: vann, vin
So English was the only Germanic language to preserve the original sound.
Moreover, the th sound sounded unvoiced ( /θ/, e g ‘to think’) or voiced (/đ/, e g ‘that’; ‘brother’) in most old Germanic languages, then it evolved into d /d/ and, sometimes into t /t/ in all modern Germanic languages except English and Icelandic:
Pgmc: þankjan, þat, brōþar;
Gothic: þagkjan, þata, bróþar;
OE: þencan, þæt, brōþor;
OFris: thinka, thet, brōther;
OS: thenkian, that, brōther;
OHG: denchen, daz, bruodar;
ON: þekkja, þat, bróđir;
English: think, that, brother;
West Frisian: tinke, dat, broer;
Dutch: denken, dat, broer;
German: denken, das, Bruder;
Icelandic: ---------, þađ, brođir;
Danish: tænke, det, broder;
Swedish: --------, ------, bror;
Norwegian: --------, ------, bror.
I hope the whole matter is clearer now.
All the best