Nine — I love you
The other day, a 100 Hour Board question prompted me to do a bit of research on a type of language change called "analogical leveling."
While I was looking for information on this phenomenon, I came across a page which listed several different types of sporadic language changes, including one I'd never heard of: immediate models.
(For the rest of this post, I'm going to discuss immediate models and not analogical leveling. If you're dying to know what analogical leveling is, it's when a word which was formerly irregular in its conjugation or declension becomes more regular.)
And immediate model is when one word changes to become like another word because those two words are frequently grouped together, often in a series. For example, the English word "femelle" turned into "female" because it was often paired with "male," and the word "February" is often pronounced without its first /r/, modeled after "January."
When I read this, something I'd learned many years ago in a Russian class finally made sense. In Indo-European languages, the word for "nine" starts with "n" in almost every language. (Numbers tend to be pretty stable over time.) In French, it's "neuf," in German "neun," in Welsh, "naw," in Greek "ennea" (the "n" gets a vowel in front, but it's still there), in Albanian, it's "nëntë," etc. In Russian, however, the word is девять ("devyat'"), which doesn't seem to make much sense.
One of my professors told me that the "n" changed into a "d" because the Russian word for "ten" (десять/"desyat") starts with "d," but at the time I didn't really understand why. Now that I know about immediate models, though, it all makes sense. "Nine" and "ten" come together in a series, so that proximity gives ten a stronger influence over nine.
Of course, this isn't a very strong effect, since this "ten-ization" only shows up in the Balto-Slavic language family, and leaves the rest of the I-E subfamilies alone.
This makes me wonder, though, if the English "four" is a product of the same change (by analogy with "five"), since most non-Germanic language sub-families have words for "four" that start with "k" or "c" or "q".