Translation of gegeneinander

So by age twelve, I had decided that I wanted to learn English and I was studying for the United States TOEFL at age twenty. Being bilingual practically from birth, makes speaking languages very easy for me.
I've been working on and off on the dictionary during the entire week, and I'll spend some more hours on it this coming weekend. Sometimes he would get a bit mixed up and use formal Castilian sometimes instead of informal.
Thank you for your kind message. I have not done anything for my Spanish because I have too much work at my job. I might write you a letter, but I'm so busy at work that I can't afford other hobbies.