I once read - I can't remember where, unfortunately - that Tchaikovsky's
pet-name for Iosif Kotek was 'Soso Kotik'. There doesn't seem to be any
reference to this on the Tchaikovsky Research site. I do know that 'kotik'
is the diminutive form of the Russian word 'kot' (a male cat), and that
Stalin's mother called her son 'Soso', which is a baby-name for boys called
Iosif. Is it conceivable that Tchaikovsky's nickname for his favourite pupil
was 'Joe the Tomcat'? This is a quite enchanting idea, bearing in mind
Tchaikovsky's infatuation with Iosif, and his witty, high-spirited and
touching account of a nocturnal jaunt they took together through the fiery
cold to dine in a private room. But is it true?
Please accept my apologies if I'm reiterating yet more drivel I've picked
up during my long and misinformed life as a Tchaikovsky fanatic!
There isn't any actual evidence that Tchaikovsky used the nickname "Soso"
for the violinist Iosif Kotek, but it is correct that Stalin's mother called
her child that way (this diminutive has its roots in the Georgian language,
rather than in Russian).
Iosif Kotek was born in Ukraine, his father was Czech by origin and his
mother Russian. Tchaikovsky only slightly modified the last name of his
former student to "Kotik" or "Kot", which means 'tomcat' in Russian.