Divide by 2
The reason most authors other than technical writers don't jump at translating is that the nuance of the writing is often lost in the translation. Between idioms and confusing words, most craftsmen (or craftswomen, please forgive) of the written word find their best skills in their native tongue. And the subsequent translation attempts seem to do no more than infuriate the editor, alienate the writer, and confound the reader. The old adage of write what you know not only applies to the subject but probably also the language.