It's so interesting because now that I am looking for it, so many of these sounds that I did not realize were related now seem like just minor variations of tongue/mouth parts positioning.
Interesting about udor, as water in ancient Greek is ύδωρ.
In IE languages, the words for water basically follow either "aqua" or "water". Finnish (it's Ugric, not IE) follows the latter, with "vesi" (combining form "vete-").
To be pedantic, Finnish is not Ugric. Hungarian is Ugric, Finnish is Finnic. They both are Finno-Ugric, a.k.a Uralic. Many non-linguist Finns mix up Finno-Ugric and Ugric.
The Proto-Uralic *weti "water" looks like it could come from IE *u̯ódr̥, *udén- "water", but that etymology is problematic because of irregular sound substitutions[0]:
- why would Uralic have *e when it's not present in the IE original?
- why would Uralic drop *r or *n at the end?
[0] Simon, Z. (2020). Urindogermanische Lehnwörter in den uralischen und finno-ugrischen Grundsprachen. Indogermanische Forschungen, 125(1), 239–266. https://doi.org/10.1515/if-2020-011
wódr̥ (PIE) → udōr (Proto-Italic) → unda (Latin) → undulātus (Late Latin) → undulate (English)
wódr̥ (PIE) → watōr (Proto-Germanic) → *watar (Proto-West Germanic) → wæter (Old English) → water (Middle English) → water (English)
In fact, I'm now noticing that the t in the Proto-Germanic line corresponds to the d in the Proto-Italic line, just as you said.