Why do some Keyserlingks use a K at the end and others not?
As I am now studying Russian, I have just figured out the reason behind this strange situation. It all comes down to the pronunciation rules of
the Russian language.  Historically, Russia ruled over the Baltic states for a long period of their history. As a result, many of our ancestors and parents. grew up in Russia and served various Tsars.  My father was born in Saint Petersburg and grew up speaking Russian. Other ancestors were in the Russian navy. An other Keyserlingk was the ambassador of the Russian Tsar to Poland.  
The original spelling of our name was without a K at the end.  However, for those families who served the Tsar, the pronunciation of the letter G sound at the end of a word forces it to sound like a K.  A soft G at the end of a word in Russian does not exist so they added a K to conform. 
End of story.
June 21, 2021
Wednesday, June 21, 2023