Etymology of Konam

The first mishnah of Nedarim mentions the concept of kinuyim, slang words that can be used to execute a neder or other types of verbal obligations. On Nedarim 10a, Rabbi Yochanan and Reish Lakish argue over the origin of these kinuyim. Rabbi Yochanan says that kinuyim are foreign terminologies (לשון אומות), while Reish Lakish says that they are artificial terms invented by Chazal. The RaN explains that לשון אומות does not mean that they're foreign words, but rather that they're mangled forms of the correct Hebrew words, as spoken by foreigners who are not so familiar with the Hebrew language. (The Rambam in Hil. Nedarim 1:16 explains similarly, except that he implies that the words were coined by Jews of different regions who mangled the words).

At first glance, I wondered how one arrived at "konam" from "korban". However, it's actually a very logical linguistic evolution. The bet in "korban" could easily shift into a mem, as both are libial sounds, changing the word to "korman". Next, the two final letters of the word can interpose to transform the word into "kornam". From here, the dropping of the gutteral reish would change the word fairly neatly into "konam". The mishnah (1:2) also mentions kinuyim such as konas and konach; I'm not sure how this evolution would have occurred, nor how nazir would become nazik or nazi'ach, nor how cheirem could become cheirek, cheirech, or cheiref, but at least these are only off by one sound (and a terminal one, at that), so the jump is less odd.