After taking a quick glance on the book of К. А. Войлова "Старославянский язык" nothing really contradicts what I posted before about Old Church Slavonic place in creation of Russian. Also, if you are presenting your source it is up to you to quote where Russian is not descendant from Old Church Slavonic, to disprove me - I have no obligation whatsoever to comb whole book and make something up that proves your point.
I had a different - more recent source that I read from Russian linguist(my memory is bad on names), where he discussed Old Church Slavonic and how it replaced most of local languages as a base to Russian and other modern East Slavic languages.
Also I think you are confused about these terms in English, where
Old Church Slavonic == Старославянский язык
Church Slavonic == Церковнославя́нский язы́к
>The Novgorod birchbark letters that were excavated over the 20th century attest some early East Slavic, noticeably different from the Old Church Slavonic language
That is correct, however what I wrote was completelly different: "All the survived early written texts of Rus are in Old Church Slavonic."
Besides, they were neither early East Slavonic or even classified as modern East Slavic and they are not directly related to Russian as well. Many of those Slavic can be classified as early Western Slavic at best.
>No, беременна is a native Slavic word and not a Swedish borrowing
It seems, that I was wrong in this one(as pregnancy in most of Slavic languages use different word, but I did not search further, where Bulgarians use similar word for pregnancy). Sadly, that also means that Old Church Slavonic replaced everything else.