I usually write the articles in Spanish and English. The English version usually has 10x move visits than the Spanish version. So I strongly recommend to write the English version too.
(I also like to write in my native language. Why use only English?)
Also, I can read in Spanish and English, some Portuguese and Italian, and a little of French and German. I had some formal education of German in primary school, but I don't remember too much. Each user has a different set of languages, but most people understand English and something else.