I have 20+ years of experience in writing I have written 10 books about various IT subjects and 6 of them are on working with Linux. I have written numerous articles for magazines. Both in English and in Dutch (my native language). When writing text the first order of business is to map out the learning path of the reader. After that I write the content, constantly keeping track of this learning path. The language that I use when writing depends on the intended audience. From very informal for students to business focused for more senior management.