While reading Snorri’s Edda, I was curious about the origin of one of Thor’s alternate names: Öku-Thor. The online version of The Prose Edda I was reading had a note that explained that the Öku part was borrowed from Finnish, as they had a similar thunder god, Ukko. That sound change just didn’t seem right. A look at Old Norse phonology made it seem like it shouldn’t have happened. I then thought that maybe a historical change in Finnish could account for the disparity. After an attempt to simply look up what Finnish probably sounded like in the Middle Ages, I found that there’s barely anything on the Internet about older forms of Finnish. A Google search for “historical stages of finnish” brings up only hits on government and theater. There is a Wikipedia page on the divergence of Finnic from Uralic, but not on the development of Finnish itself. I finally found a page on FrathWiki, a conlang and phonology wiki, that has many stages of Finnish, but I’m not sure about the quality of the source, translation, or transfer to wiki.
You might say that a change from [u] to [ø] over hundreds of years isn’t that big of a change, but Old Norse doesn’t show that kind of vowel shift (rotation, really). Also, as Finnish itself shows in its borrowings from Proto-Germanic, Finnish has not changed drastically since then, so borrowed words haven’t changed much. Which brings me to my next point: if Öku was borrowed into Old Norse from Old(?) Finnish then it would have followed the pattern usual of borrowings to be phonologically assimilated, resulting in either a form unrecognizable as foreign (and then subject to ON’s regular sound changes) or it would have violated the rules of Old Norse phonotactics and thus been more resistant to sound change, having rare environments to be selected. The latter case can be seen in words adopted into English like guacamole or chipotle. Then again, people may not recognize the foreign word, especially in the time before writing, and just impose their perception of the pronunciation on it. The problem with that hypothesis for Öku though is that Ukko/Uko does not seem to violate Old Norse phonotactics or present any sounds that Old Norse speakers would have had trouble with. That makes me wonder what the Old Finnish vowel was. Since the apparent sounds are in Old Norse, then, by the first hypothesis, it should follow Old Norse sound changes, one of which was not [u] → [ø].
We have a few options for what really happened:
- The reverse [ø] → [u] happened from Old Finnish to Modern Finnish
- The ‹u› in Ukko is actually centralized [ʉ] in Modern Finnish, as Wikipedia claims, and was so at the time Old Norse borrowed it, leading to the interpretation [ø]
- The Old Finnish vowel was something other than [ø] or [u] or [ʉ], yet confusable by an Old Norse speaker for [ø]
- It was borrowed from a minority dialect of Finnish
- It was from the Estonian Uku, which gets the [u] at the end and might also have a historic form that would work
- It was borrowed from another Finnic language or passed through an intermediate language
- Ukko does, in fact, violate Old Norse phonotactics, possibly leading to some of the options below:
- It’s some sort of hypercorrective metathesis: [o] and [u] switch Ukko → Oku, but the sound of [u] to the Old Norse ear triggers umlaut/fronting to [ø]
- Öku is not the spelling from the manuscript, thus completely false, and the name came from simple metathesis Ukko → Oku, Öku then likely came to English through German Oku → Öku
- The Proto-Finnic form was *[uxko] and that did not match Old Norse phonotactics, leading to Öku
- The Proto-Finnic form was *[βikːo] which led to Old Norse Öku, possibly by way of *[øko]
- The borrowing was made long before Old Norse and was thus subject to Germanic sound changes
- Öku was borrowed into Finnish from Old Norse or Germanic
- It actually does come from áka ‘to drive’ and Cleasby-Vigfússon is wrong
Needless to say it looks like there needs to be some more work on the history of Finnish and/or it needs to be translated into English and/or it needs to be put on the Internet.