"Город, смород" vs. "град, смрад" — is there any rhyme and reason behind all the metatheses of Modern Russian vs. Old Church Slavonic?

Question

I am sure you've come across these word pairings before:

• город — град
• смород — смрад
• скользкий — склизкий
• ворота — врата
• ворон — враний
• ворог — враг
• холод — хлад (cf. хладнокровный)
• and so on and so forth

You know you can easily add dozens of examples yourself, off the top of your head.

Now, the way I overheard it somewhere (perhaps in grade school), the град, смрад, вран-, врат- etc. variants all come from Old Church Slavonic, while the город, ворот, ворон etc. are "proper Modern Russian", for lack of a better description. And as I said, there are literally dozens if not hundreds of other examples. There is really an obvious pattern here. And by the looks of it, it's always metathesis at work. And by the looks of it, the Old Church Slavonic variant is almost always the more "formal", "literary", "elevated", poetic one, while the other variants are more colloquial, down-to-earth.

Why would that be? What is the reason behind so many Russian words having been "metathesized" vs. their Old Church Slavonic equivalents, getting that more "elevated" poetic version? Did that happen gradually? Or did the variations sort of develop in parallel over time?

I must say I've never encountered anything quite like this before in any other language I'm remotely familiar with. I'd be most grateful if you could point me to any research on this.

Answer 1

The words with -оло- / -оро- / -ере- / -ело- are typical of the East Slavic languages, not only of Russian, but also of Ukrainian and Belarusian. That phenomenon is called "полногласие" (pleophony). It is a characteristic feature of the Eastern Slavic languages, West and South Slavic languages don't have that. In the South Slavic languages (Old Church Slavonic (OCS) is one of them) these pleophonic sound combinations correspond to -ра- / -ла- / -ре- / -ле- which can be seen in the right part of you word list, the words in the right part are borrowings from OCS.

The words of the OCS origin are more elevated because OCS had always a higher, more spiritual, more learned, more official status, it was associated with the church, literature, learning, government, while Russian was a colloquial, spoken language lacking that prestige.

As for the metathesis, it would be a mistake to think that the original form of those words is the way they sound in OCS, and they simply got transformed in Russian. The point is, the Proto-Slavic sound combinations *TorT, *TolT, *TerT, *TelT ("T" means any consonant) developed into different sound combinations in different Slavic dialects of those times, giving the pleophonic sequences in East Slavic languages, and -ра- / -ла- etc., in South Slavic. In other words, Russian and OCS are sister languages, in those words their mother language, Proto-Slavic, had sound combinations which were different from both Russian and OSC.

Having pairs of words in a language that have the same etymological source, but differ in a way, can be seen in lots of languages across the world. Such pairs (or even bigger groups of words) are called doublets or etymological twins. English has very many of them. The only difference of Russian doublets is that Russian heavily borrowed words from a very closely related language, OCS, while English borrowed them from distantly related languages, although English - Old Norse doublets are very close, like shirt vs. skirt.