When I was born (in the cold, tundra of Russia….I’m totally kidding, I was born in July in Moscow which is just about as hot as NYC in the summer), my parents named me Ekaterina. Or, Katia.

At the not-so-ripe age of 12, we moved to New Jersey, USA. My parents got some advice about helping us learn English faster by putting us in school almost immediately following our move. (I’m not going to lie to you, I’m still a tad bitter about this since I already finished 6th grade early in Moscow.)
On the first day of school, the school counselor sat my dad and me down and told us that we needed to register. She asked my dad what my name was and he said, “Catherine.” I watched them closely, not able to understand a single word being said. The counselor wrote out about 5 different ways to spell “Catherine” and let him choose.
My dad chose “Catherine.”
Because it looked pretty.
There is no “C” in the Russian alphabet.

When I finally got to my classroom, the teacher introduced me to the class (while I stood there, not understanding a single word) and wrote out some nicknames. Apparently there were 4 other Catherines in the room and she needed to differentiate us. My new nickname was “Cathy.” I sat down in my new seat and introduced myself to my designated “buddy.” She was Russian and translated the whole thing to me. I was too confused and overwhelmed to say anything.
In seventh grade we moved to Massachusetts. My new school-mates automatically called me “Cathy.” I was already beginning to resent that name.
By High School, a lot of my friends started calling me “Kat” after listening to me complain about my name and its spelling. “Kat'” was short for “Katia.”
Side story - I don’t go by “Katia” because I love my name, but have very little patience for its mispronunciation in the American language. (It’s Kah-tya not Kah-tee-a).
By the time I finished High School, I decided that I would start over in College. on my first say I introduced myself to my roommates as “Catherine.” Then one of my friends came by and asked for “Kat.” It stuck.
I tried again on my first day of work, but Jon (the hubs, then friend from college) called me “Kat” on the first day. I had to explain the whole “Catherine with a C” and “Kat with a K” fiasco.
When we got married, I thought it would be the perfect time to (finally) change my first name to “Katherine.” Apparently it takes a court date to change your first name (and only a marriage certificate to change your last name). I bailed on the process.
So, Hi, I’m Kat, short for Catherine….it’s a long story.