Verb conjugation of "alternate" in English

It looks like we need to invite Erika again to my home, once the cake is ready. Of course, this should be done before Sunday to stay in the chocolate cake race. We should buy cream too.
Yes, my Spanish is much better than your German, but it is not true that I do not want to learn with you. I think this is not an issue. Where do you come from in the U.S.? East or West coast?
I am back in Switzerland, and the weather makes me crazy. Shall I write you on Vocabulix or to your regular email address? I have been working 20 years as an employee for a German company.